feat(t-paliad-088): Event Types for deadlines — schema + service + handlers (PR-1)

Migration 030 adds paliad.event_types and paliad.deadline_event_types
junction. ~43 firm-wide seeds biased toward submissions (25 UPC
submissions + 8 UPC decisions/orders/hearings + 5 EPO + 4 DPMA/DE + 1
cross-jurisdiction). UPC-seeded rows carry a loose trigger_event_id
column (no FK constraint per Q2: event_types leads, trigger_events
follows). RLS policies are defense-in-depth — primary enforcement is
in the Go service layer. Per Q6, any authenticated user can create
firm-wide types; admins moderate via the soft-delete archive lever.

EventTypeService: List (firm-wide ∪ own-private), GetByID, Create
(slug auto-derived, supports diacritics → ASCII), Update (author OR
admin-on-firm-wide), SuggestSimilar (powers the duplicate-warning in
the add modal), AttachToDeadlineTx + ValidateForUser + ListForDeadlines
for the junction.

DeadlineService gains an EventTypeService dependency and now:
- accepts event_type_ids on Create / Update / CreateBulk
- attaches them in the same transaction as the deadline insert
- hydrates EventTypeIDs on every Get / List / ListForProject
- supports the multi-select Typ filter via ListFilter.EventTypeIDs +
  IncludeUntyped (UNION semantics within types, AND-intersected with
  Status/Project)

AgendaService gets the same Typ filter on its deadline side;
appointments are unaffected.

API:
- GET /api/event-types?category=&jurisdiction=
- GET /api/event-types/suggest?q=
- POST /api/event-types
- PATCH /api/event-types/{id}        (set archive=true to hide)
- GET /api/deadlines?event_type=<uuid>,<uuid>,none
- GET /api/agenda?event_type=<uuid>,<uuid>,none
- POST/PATCH /api/deadlines accept event_type_ids: [uuid]

go build / go vet / go test ./... clean.

Frontend (picker + custom-add modal + multi-select filter) follows in
PR-2. Admin moderation panel deferred to t-paliad-089 follow-up.

internal/models/models.go

@@ -181,6 +181,11 @@ type Deadline struct {
 	CreatedBy       *uuid.UUID `db:"created_by"        json:"created_by,omitempty"`
 	CreatedAt       time.Time  `db:"created_at"        json:"created_at"`
 	UpdatedAt       time.Time  `db:"updated_at"        json:"updated_at"`
+
+	// EventTypeIDs lists the paliad.event_types attached to this deadline
+	// via the paliad.deadline_event_types junction. Always present (never
+	// nil) once the row has been hydrated by DeadlineService.
+	EventTypeIDs []uuid.UUID `db:"-" json:"event_type_ids"`
 }
 
 // DeadlineWithProject enriches a Deadline with parent-Project display fields
@@ -403,3 +408,51 @@ type EventDeadlineRuleCode struct {
 	RuleCode        string `db:"rule_code"         json:"rule_code"`
 	SortOrder       int    `db:"sort_order"        json:"sort_order"`
 }
+
+// EventType is a user-facing categorization tag for a Deadline (Statement
+// of Defence, Reply, Decision on the merits, EPO opposition, …). Distinct
+// from TriggerEvent: TriggerEvents are calc-engine state (UPC-only,
+// verbatim youpc imports), EventTypes are the broader taxonomy users
+// pick from when creating a Deadline.
+//
+// CreatedBy NULL on system seeds; set on user-created rows. IsFirmWide
+// true for seeds and any firm-wide row a user explicitly publishes;
+// false for personal taxonomy. TriggerEventID is a loose linkage column
+// (no FK constraint) populated only for seeded UPC rows.
+type EventType struct {
+	ID             uuid.UUID  `db:"id"               json:"id"`
+	Slug           string     `db:"slug"             json:"slug"`
+	LabelDE        string     `db:"label_de"         json:"label_de"`
+	LabelEN        string     `db:"label_en"         json:"label_en"`
+	Category       string     `db:"category"         json:"category"`
+	Jurisdiction   *string    `db:"jurisdiction"     json:"jurisdiction,omitempty"`
+	Description    string     `db:"description"      json:"description"`
+	TriggerEventID *int64     `db:"trigger_event_id" json:"trigger_event_id,omitempty"`
+	CreatedBy      *uuid.UUID `db:"created_by"       json:"created_by,omitempty"`
+	IsFirmWide     bool       `db:"is_firm_wide"     json:"is_firm_wide"`
+	ArchivedAt     *time.Time `db:"archived_at"      json:"archived_at,omitempty"`
+	CreatedAt      time.Time  `db:"created_at"       json:"created_at"`
+	UpdatedAt      time.Time  `db:"updated_at"       json:"updated_at"`
+}
+
+// EventTypeCategory enumerates the values allowed on event_types.category.
+// Mirrors the CHECK constraint in migration 030.
+const (
+	EventTypeCategorySubmission = "submission"
+	EventTypeCategoryDecision   = "decision"
+	EventTypeCategoryOrder      = "order"
+	EventTypeCategoryService    = "service"
+	EventTypeCategoryFee        = "fee"
+	EventTypeCategoryHearing    = "hearing"
+	EventTypeCategoryOther      = "other"
+)
+
+// EventTypeJurisdiction enumerates the values allowed on
+// event_types.jurisdiction (NULL is also valid).
+const (
+	EventTypeJurisdictionUPC  = "UPC"
+	EventTypeJurisdictionEPO  = "EPO"
+	EventTypeJurisdictionDPMA = "DPMA"
+	EventTypeJurisdictionDE   = "DE"
+	EventTypeJurisdictionAny  = "any"
+)