Merge: t-paliad-165 — Regel ↔ Typ collapse via auto-link on the deadline create form

Two slices on mai/noether/collapse-regel-typ-on:

  0c12644  feat(deadline-rules): expose concept's canonical event_type per rule
  1e97ecc  feat(deadlines/new): auto-link Typ to Regel's concept

What ships:

- New junction paliad.deadline_concept_event_types maps every
  paliad.deadline_concepts row to its canonical paliad.event_types
  row(s). Many-to-many for concepts with multiple legitimate variants
  (statement-of-defence ↔ base + with_ccr + no_ccr; opposition across
  EPO + DPMA). Exactly one row per concept marked is_default = true
  by a partial unique index — that is the row the deadline form
  auto-fills with.

- Backend: paliad.deadline_rules_with_concept_event_type view + the
  deadline-rules read path now expose the rule's default concept
  event_type so the form has the auto-fill target without an extra
  round-trip.

- Frontend deadline create / edit form: when the user picks a Regel,
  the Typ chip auto-fills with the rule's concept's default event_type.
  A small "vorgegeben durch Regel — überschreiben?" hint sits next to
  the chip so the auto-fill is visible. The user can override (free-
  text or pick a different type); the override is explicit, no
  blocking validation.

- Free-text Typ stays available — manual deadlines without a
  matching rule (e.g. "Call me" reminders) keep working as today.

Migration housekeeping
======================

noether authored her migration as 072 on her branch but main had
already taken 072 via minkowski's t-paliad-164 (paliad.projects.our_side).
Renumbered to 073 during merge resolution to resolve the same-number
collision. Added IF NOT EXISTS guards on CREATE TABLE / CREATE INDEX
for re-run safety (the seed INSERT already had ON CONFLICT DO NOTHING).

Live tracker bumped 72 → 73 in the same operation: both effects
(our_side column AND deadline_concept_event_types table) were
applied to live during dev (each worker against the same DB), so
the tracker advance reflects schema reality. Next deploy sees
tracker=73 with file 073 present and has nothing to apply.

Refs m/paliad#18.

internal/models/models.go

@@ -475,6 +475,12 @@ type DeadlineRule struct {
 	AltRuleCode      *string    `db:"alt_rule_code"      json:"alt_rule_code,omitempty"`
 	AnchorAlt        *string    `db:"anchor_alt"         json:"anchor_alt,omitempty"`
 	ConceptID        *uuid.UUID `db:"concept_id"         json:"concept_id,omitempty"`
+	// ConceptDefaultEventTypeID is the canonical paliad.event_types row for
+	// this rule's concept (joined via paliad.deadline_concept_event_types
+	// where is_default = true). Lets the deadline create form auto-populate
+	// the Typ chip when the user picks this rule. Hydrated by the service
+	// layer; not a column. NULL when the concept has no mapped event_type.
+	ConceptDefaultEventTypeID *uuid.UUID `db:"-" json:"concept_default_event_type_id,omitempty"`
 	LegalSource      *string    `db:"legal_source"       json:"legal_source,omitempty"`
 	IsSpawn          bool       `db:"is_spawn"           json:"is_spawn"`
 	SpawnLabel       *string    `db:"spawn_label"        json:"spawn_label,omitempty"`