feat(litigationplanner): embedded UPC snapshot + generator (Slice C, m/paliad#124 §19)

Lays the foundation for youpc.org's cross-repo integration: an
in-package UPC subset of paliad's deadline corpus, embedded as JSON,
that any consumer can use to run the litigationplanner engine without
DB access.

Generator (cmd/gen-upc-snapshot):
  - Reads paliad's live DB (DATABASE_URL), applies pending migrations
    to match schema HEAD, SELECTs the UPC subset
    (proceeding_types WHERE jurisdiction='UPC' AND is_active=true,
    deadline_rules WHERE lifecycle_state='published' AND is_active=true
    on those proceedings, referenced trigger_events, DE+UPC holidays,
    UPC courts).
  - Writes pretty-printed JSON to
    pkg/litigationplanner/embedded/upc/{proceeding_types, rules,
    trigger_events, holidays, courts, meta}.json.
  - Idempotent — same DB state → same output (modulo
    meta.generated_at + auto-versioned suffix).
  - Date-stamped versioning (YYYY-MM-DD-N) with same-day suffix bump.
  - Operator runbook in cmd/gen-upc-snapshot/README.md.

Embedded subpackage (pkg/litigationplanner/embedded/upc/):
  - embed.go    — //go:embed *.json + LoadMeta()
  - snapshot.go — SnapshotCatalog (full lp.Catalog impl: LoadProceeding
    / LoadProceedingByID / LoadRuleByID / LoadRuleByCode /
    LoadRulesByTriggerEvent / LoadTriggerEventsByIDs / LookupEvents);
    O(1) map lookups; LookupEvents linear over the < 100-row UPC corpus.
  - holidays.go — SnapshotHolidayCalendar implementing lp.HolidayCalendar
    (IsNonWorkingDay / Adjust* with structured AdjustmentReason).
  - courts.go   — SnapshotCourtRegistry implementing lp.CourtRegistry.
  - Compile-time assertions (_ lp.X = (*Snapshot*)(nil)) catch
    interface drift.

Wire-up for consumers:
  cat, _ := upc.NewCatalog()
  hc, _  := upc.NewHolidayCalendar()
  cr, _  := upc.NewCourtRegistry()
  timeline, _ := lp.Calculate(ctx, "upc.inf.cfi", "2026-05-26",
                              lp.CalcOptions{}, cat, hc, cr)

Tests (snapshot_test.go, all DB-free):
  - meta parses cleanly, non-zero counts
  - LoadProceeding(upc.inf.cfi) returns expected proc + rules
  - LoadProceeding(unknown) returns ErrUnknownProceedingType
  - LookupEvents(Jurisdiction:UPC, all-following) covers corpus
  - LookupEvents(party=defendant, next) scopes anchors correctly
  - engine end-to-end via lp.Calculate against the embedded snapshot
  - holiday calendar (weekends, DE closures, UPC vacation block)
  - court registry (empty courtID fallback, known + unknown court)

Placeholder data shipped (2 proceedings, 2 rules, 5 holidays, 2
courts) so tests run without a live DB. Operator regenerates against
prod via `make snapshot-upc` once migrations 134 (B1) and 135 (B3)
have landed on prod — see cmd/gen-upc-snapshot/README.md for the
runbook. The placeholder's meta.version is suffixed `-placeholder`
to make the regeneration delta obvious.

Makefile target:
  make snapshot-upc — wraps the generator + reruns the snapshot tests

Design (§19 of docs/design-litigation-planner-2026-05-26.md):
  - Embedding format: go:embed JSON (diff-friendly, no compile coupling)
  - Generator entry: cmd/gen-upc-snapshot/main.go (idiomatic Go cmd path)
  - Versioning: meta.json carries semver + generated_at + paliad_commit
  - Regeneration: manual via Make target or `go generate`; no CI cron in v1
  - Out of scope: snapshot signing, DE/EPA/DPMA snapshots, snapshot
    diff tooling

Acceptance:
  - go build clean, go test all green (incl. 6 new tests in
    pkg/litigationplanner/embedded/upc, all DB-free)
  - SnapshotCatalog passes the compile-time lp.Catalog assertion
  - Generator binary builds + runs (Idempotence verified by re-running
    against the same source data)

cmd/gen-upc-snapshot/README.md

@@ -0,0 +1,59 @@
+# gen-upc-snapshot
+
+Regenerates the embedded UPC snapshot consumed by
+`pkg/litigationplanner/embedded/upc`. Slice C of the litigation-planner
+extraction (m/paliad#124 §19). See
+`docs/design-litigation-planner-2026-05-26.md` §19 for the full design.
+
+## When to regenerate
+
+After any change that affects the public UPC rule corpus:
+
+- new rules merged via the admin rule-editor
+- a deadline-rule migration that touches UPC rows
+- a `paliad.holidays` update (new public holidays / vacation runs)
+- a `paliad.courts` update (new UPC LD opens, etc.)
+- a `paliad.proceeding_types` change for `jurisdiction = 'UPC'`
+
+The snapshot is operator-controlled — there is no CI regeneration in v1.
+
+## How to regenerate
+
+```sh
+make snapshot-upc
+```
+
+or directly:
+
+```sh
+DATABASE_URL=postgres://...  go run ./cmd/gen-upc-snapshot
+```
+
+Flags:
+
+| Flag            | Default                                | Purpose |
+|-----------------|----------------------------------------|---------|
+| `-output`       | `./pkg/litigationplanner/embedded/upc` | directory to write JSON files into |
+| `-version`      | auto-derived (`YYYY-MM-DD-N`)          | override the snapshot version |
+| `-source-label` | empty                                  | text label written to `meta.json` (`paliad-prod`, `paliad-dev`, …) |
+
+The generator:
+
+1. Applies pending migrations against `DATABASE_URL` (snapshot always matches schema HEAD).
+2. SELECTs UPC active proceeding_types + their published+active rules + referenced trigger_events + DE/UPC holidays + UPC courts.
+3. Writes pretty-printed JSON to `<output>/{proceeding_types,rules,trigger_events,holidays,courts,meta}.json`.
+
+## Idempotence
+
+Running twice with the same DB state produces the same JSON (modulo `meta.generated_at`). Diff-friendly in git.
+
+## Versioning
+
+`meta.json.version` uses `YYYY-MM-DD-N` where N starts at 1 and increments on same-day regenerations. The generator reads the existing `meta.json` and bumps automatically.
+
+## After regeneration
+
+1. Review the diff: `git diff pkg/litigationplanner/embedded/upc/`.
+2. Run tests: `go test ./pkg/litigationplanner/embedded/upc/...`.
+3. Commit with a message like `chore(snapshot): regenerate UPC snapshot (<reason>)`.
+4. Notify any downstream consumer (youpc.org) that a new paliad release is available.

cmd/gen-upc-snapshot/main.go

@@ -0,0 +1,301 @@
+// Command gen-upc-snapshot reads paliad's live deadline corpus and
+// writes the UPC subset as JSON files under
+// pkg/litigationplanner/embedded/upc/. The package's embedded
+// catalog/holiday/court implementations then serve this data without
+// any DB roundtrip — letting youpc.org (or any future consumer) run
+// the litigationplanner engine against the canonical UPC rule set.
+//
+// Slice C (m/paliad#124 §19). See docs/design-litigation-planner-2026-05-26.md
+// §19 for the full design.
+//
+// Usage:
+//
+//	DATABASE_URL=postgres://... go run ./cmd/gen-upc-snapshot \
+//	    [-output ./pkg/litigationplanner/embedded/upc] \
+//	    [-version 2026-05-26-1] \
+//	    [-source-label paliad-dev-supabase]
+//
+// The generator applies migrations against DATABASE_URL before
+// SELECTing (so the snapshot always matches schema HEAD). Idempotent —
+// running twice with the same DB state produces the same JSON.
+package main
+
+import (
+	"context"
+	"encoding/json"
+	"flag"
+	"fmt"
+	"log"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"strings"
+	"time"
+
+	"github.com/jmoiron/sqlx"
+	_ "github.com/lib/pq"
+
+	"mgit.msbls.de/m/paliad/internal/db"
+	"mgit.msbls.de/m/paliad/pkg/litigationplanner"
+)
+
+const (
+	defaultOutput      = "./pkg/litigationplanner/embedded/upc"
+	defaultSourceLabel = ""
+)
+
+// Meta is the version block written to meta.json. The embedded sub-
+// package re-defines this type so consumers can decode it without
+// importing the cmd; the cmd holds the canonical write shape.
+type Meta struct {
+	Version           string    `json:"version"`
+	GeneratedAt       time.Time `json:"generated_at"`
+	PaliadCommit      string    `json:"paliad_commit,omitempty"`
+	SourceDBLabel     string    `json:"source_db_label,omitempty"`
+	RuleCount         int       `json:"rule_count"`
+	ProceedingCount   int       `json:"proceeding_count"`
+	TriggerEventCount int       `json:"trigger_event_count"`
+	HolidayCount      int       `json:"holiday_count"`
+	CourtCount        int       `json:"court_count"`
+}
+
+// EmbeddedHoliday is the holiday row shape the embedded snapshot
+// stores. JSON tags mirror paliad.holidays so the generator's SELECT
+// scans onto it directly + the embedded HolidayCalendar reads the
+// same tag.
+type EmbeddedHoliday struct {
+	Date        string  `db:"date_iso" json:"date"`
+	Name        string  `db:"name" json:"name"`
+	Country     *string `db:"country" json:"country,omitempty"`
+	Regime      *string `db:"regime" json:"regime,omitempty"`
+	State       *string `db:"state" json:"state,omitempty"`
+	HolidayType string  `db:"holiday_type" json:"holiday_type"`
+}
+
+// EmbeddedCourt is the court row shape the embedded snapshot stores.
+type EmbeddedCourt struct {
+	ID        string  `db:"id" json:"id"`
+	Code      string  `db:"code" json:"code"`
+	NameDE    string  `db:"name_de" json:"name_de"`
+	NameEN    string  `db:"name_en" json:"name_en"`
+	Country   string  `db:"country" json:"country"`
+	Regime    *string `db:"regime" json:"regime,omitempty"`
+	CourtType string  `db:"court_type" json:"court_type"`
+	ParentID  *string `db:"parent_id" json:"parent_id,omitempty"`
+	SortOrder int     `db:"sort_order" json:"sort_order"`
+}
+
+func main() {
+	output := flag.String("output", defaultOutput, "directory to write JSON files into")
+	version := flag.String("version", "", "explicit snapshot version (auto-derived if empty)")
+	sourceLabel := flag.String("source-label", defaultSourceLabel, "label for source_db in meta.json")
+	flag.Parse()
+
+	url := os.Getenv("DATABASE_URL")
+	if url == "" {
+		log.Fatal("DATABASE_URL must be set")
+	}
+
+	if err := db.ApplyMigrations(url); err != nil {
+		log.Fatalf("apply migrations: %v", err)
+	}
+
+	pool, err := sqlx.Connect("postgres", url)
+	if err != nil {
+		log.Fatalf("connect: %v", err)
+	}
+	defer pool.Close()
+
+	ctx := context.Background()
+	if err := run(ctx, pool, *output, *version, *sourceLabel); err != nil {
+		log.Fatalf("snapshot: %v", err)
+	}
+}
+
+func run(ctx context.Context, pool *sqlx.DB, output, version, sourceLabel string) error {
+	if err := os.MkdirAll(output, 0o755); err != nil {
+		return fmt.Errorf("mkdir output: %w", err)
+	}
+
+	// 1. Proceeding types — UPC + active only. The unified upc.apl row
+	// from B1 mig 134 is included; the 3 archived old appeal codes
+	// (is_active=false) are filtered out by the WHERE.
+	var procs []litigationplanner.ProceedingType
+	if err := pool.SelectContext(ctx, &procs, `
+		SELECT id, code, name, name_en, description, jurisdiction,
+		       category, default_color, sort_order, is_active,
+		       trigger_event_label_de, trigger_event_label_en,
+		       appeal_target
+		  FROM paliad.proceeding_types
+		 WHERE jurisdiction = 'UPC' AND is_active = true
+		 ORDER BY sort_order, id`); err != nil {
+		return fmt.Errorf("select proceeding_types: %w", err)
+	}
+
+	if len(procs) == 0 {
+		return fmt.Errorf("no active UPC proceeding_types — refusing to write empty snapshot")
+	}
+
+	procIDs := make([]int, 0, len(procs))
+	for _, p := range procs {
+		procIDs = append(procIDs, p.ID)
+	}
+
+	// 2. Deadline rules — published + active rules for those proceedings.
+	const ruleCols = `id, proceeding_type_id, parent_id, submission_code, name, name_en,
+		description, primary_party, event_type, duration_value,
+		duration_unit, timing, rule_code, deadline_notes, deadline_notes_en, sequence_order,
+		alt_duration_value, alt_duration_unit, alt_rule_code,
+		anchor_alt, concept_id, legal_source, is_spawn, spawn_label, is_active,
+		created_at, updated_at,
+		trigger_event_id, spawn_proceeding_type_id, combine_op, condition_expr,
+		priority, is_court_set, lifecycle_state, draft_of, published_at,
+		choices_offered, applies_to_target`
+
+	q, args, err := sqlx.In(`
+		SELECT `+ruleCols+`
+		  FROM paliad.deadline_rules
+		 WHERE proceeding_type_id IN (?)
+		   AND is_active = true
+		   AND lifecycle_state = 'published'
+		 ORDER BY proceeding_type_id, sequence_order`, procIDs)
+	if err != nil {
+		return fmt.Errorf("build rules IN: %w", err)
+	}
+	q = pool.Rebind(q)
+	var rules []litigationplanner.Rule
+	if err := pool.SelectContext(ctx, &rules, q, args...); err != nil {
+		return fmt.Errorf("select rules: %w", err)
+	}
+
+	// 3. Trigger events referenced by any UPC rule's trigger_event_id.
+	triggerIDSet := make(map[int64]struct{})
+	for _, r := range rules {
+		if r.TriggerEventID != nil {
+			triggerIDSet[*r.TriggerEventID] = struct{}{}
+		}
+	}
+	var triggers []litigationplanner.TriggerEvent
+	if len(triggerIDSet) > 0 {
+		triggerIDs := make([]int64, 0, len(triggerIDSet))
+		for id := range triggerIDSet {
+			triggerIDs = append(triggerIDs, id)
+		}
+		q, args, err := sqlx.In(`
+			SELECT id, code, name, name_de, description, is_active, created_at
+			  FROM paliad.trigger_events
+			 WHERE id IN (?)
+			 ORDER BY id`, triggerIDs)
+		if err != nil {
+			return fmt.Errorf("build triggers IN: %w", err)
+		}
+		q = pool.Rebind(q)
+		if err := pool.SelectContext(ctx, &triggers, q, args...); err != nil {
+			return fmt.Errorf("select trigger_events: %w", err)
+		}
+	}
+
+	// 4. Holidays — DE national + UPC regime entries. The embedded
+	// calendar serves UPC computations so both axes matter.
+	var holidays []EmbeddedHoliday
+	if err := pool.SelectContext(ctx, &holidays, `
+		SELECT to_char(date, 'YYYY-MM-DD') AS date_iso,
+		       name, country, regime, state, holiday_type
+		  FROM paliad.holidays
+		 WHERE country = 'DE' OR regime = 'UPC'
+		 ORDER BY date, name`); err != nil {
+		return fmt.Errorf("select holidays: %w", err)
+	}
+
+	// 5. Courts — UPC subset.
+	var courts []EmbeddedCourt
+	if err := pool.SelectContext(ctx, &courts, `
+		SELECT id, code, name_de, name_en, country, regime, court_type, parent_id, sort_order
+		  FROM paliad.courts
+		 WHERE is_active = true
+		   AND (regime = 'UPC' OR court_type LIKE 'upc%')
+		 ORDER BY sort_order, id`); err != nil {
+		return fmt.Errorf("select courts: %w", err)
+	}
+
+	// 6. Compose meta.
+	meta := Meta{
+		Version:           resolveVersion(version, output),
+		GeneratedAt:       time.Now().UTC().Truncate(time.Second),
+		PaliadCommit:      gitCommitShort(),
+		SourceDBLabel:     sourceLabel,
+		RuleCount:         len(rules),
+		ProceedingCount:   len(procs),
+		TriggerEventCount: len(triggers),
+		HolidayCount:      len(holidays),
+		CourtCount:        len(courts),
+	}
+
+	// 7. Write each file.
+	files := []struct {
+		name string
+		data any
+	}{
+		{"proceeding_types.json", procs},
+		{"rules.json", rules},
+		{"trigger_events.json", triggers},
+		{"holidays.json", holidays},
+		{"courts.json", courts},
+		{"meta.json", meta},
+	}
+	for _, f := range files {
+		path := filepath.Join(output, f.name)
+		buf, err := json.MarshalIndent(f.data, "", "  ")
+		if err != nil {
+			return fmt.Errorf("marshal %s: %w", f.name, err)
+		}
+		buf = append(buf, '\n')
+		if err := os.WriteFile(path, buf, 0o644); err != nil {
+			return fmt.Errorf("write %s: %w", path, err)
+		}
+	}
+
+	log.Printf("snapshot written: version=%s rules=%d proceedings=%d triggers=%d holidays=%d courts=%d → %s",
+		meta.Version, meta.RuleCount, meta.ProceedingCount,
+		meta.TriggerEventCount, meta.HolidayCount, meta.CourtCount, output)
+	return nil
+}
+
+// resolveVersion picks a date-stamped version slug, bumping the suffix
+// past any pre-existing same-day version found in the existing
+// meta.json. If the caller passed -version, that wins.
+func resolveVersion(explicit, output string) string {
+	if explicit != "" {
+		return explicit
+	}
+	today := time.Now().UTC().Format("2006-01-02")
+	// Read prior meta to detect same-day collisions.
+	prior, err := os.ReadFile(filepath.Join(output, "meta.json"))
+	if err != nil {
+		return today + "-1"
+	}
+	var pm Meta
+	if err := json.Unmarshal(prior, &pm); err != nil {
+		return today + "-1"
+	}
+	if !strings.HasPrefix(pm.Version, today+"-") {
+		return today + "-1"
+	}
+	// Same day: bump the suffix.
+	suffix := pm.Version[len(today)+1:]
+	var n int
+	if _, err := fmt.Sscanf(suffix, "%d", &n); err != nil {
+		return today + "-1"
+	}
+	return fmt.Sprintf("%s-%d", today, n+1)
+}
+
+// gitCommitShort returns the short SHA of the paliad checkout. Best-
+// effort — empty string when we're not in a git checkout.
+func gitCommitShort() string {
+	out, err := exec.Command("git", "rev-parse", "--short", "HEAD").Output()
+	if err != nil {
+		return ""
+	}
+	return strings.TrimSpace(string(out))
+}