feat(trigger-service): manual receiver + REST CRUD (TS-IMPL-015)

[toddysm]

TS-IMPL-015 — Manual Receiver + REST CRUD

Implements the operator-facing REST surface for trigger subscriptions and a
manual :fire that drives the same normalize → match → dispatch pipeline an
inbound event takes. Closes #645.

Endpoints (api/routes/subscriptions.py)

• POST /v1/workspaces/{ws}/triggers — create a start subscription (201)
• GET /v1/workspaces/{ws}/triggers/{id} — read one back
• PATCH /v1/workspaces/{ws}/triggers/{id} — amend selector / mapping / target / state
• DELETE /v1/workspaces/{ws}/triggers/{id} — soft-delete → state expired (204)
• POST /v1/workspaces/{ws}/triggers/{id}:fire — fire now → { runId }

Behaviour

• Selectors validated through the CEL evaluator on create/patch → invalid → 422.
• :fire returns the started runId; a paused/non-matching subscription →
  409 trigger.api.subscription_not_fireable; a subscription with no target
  workflow version dead-letters → 502 trigger.dispatch_failed; a
  redelivered fire collapses in the dedup window → 409 trigger.dedup_duplicate.
• Unknown id → 404 trigger.subscription_not_found on every route.
• RBAC delegated to the call-context middleware via require_permission
  (trigger:subscriptions:{read,write,delete,fire}).

Supporting changes

• api/errors.py — RFC 7807 application/problem+json envelope (mirrors the
  workflow-service convention): a TriggerError handler over the locked domain
  taxonomy plus route-local trigger.api.* kinds, and a
  RequestValidationError handler.
• stores — SubscriptionReadable capability Protocol + async
  SubscriptionStore.get; backends lacking the capability raise
  SubscriptionReadUnsupportedError (the Postgres read surface lands in a later task).
• app.py / dependencies.py — the lifespan builds a shared SelectorEvaluator
  and a Dispatcher (over an owned httpx client reaching the Workflow Service
  through Dapr, closed at shutdown); create_app gains a dispatcher injection
  seam for tests; Problem+JSON handlers + router wired in.
• models.py — ManualFireRequest / ManualFireResult.

Design constraints honoured

• The locked SPL metadata surface is write-only for subscriptions, so read-back
  uses an optional capability Protocol satisfied by the in-process backend and
  DELETE is a soft-delete (expired is terminal — no row delete exists).
• input_mapping placeholder resolution is forwarded literally (deferred to a
  later task); manual fire is start-only per classify.

Verification

ruff check . + ruff format --check . + mypy src tests clean.
pytest: 378 passed, 99.1% coverage (subscriptions route 98.9%,
api/errors 95.8%).

[Copilot]

Pull request overview

Adds an operator-facing subscription REST API to the trigger-service, including a manual :fire endpoint that drives the same normalize → match → dispatch pipeline as inbound events, and introduces an RFC7807 Problem+JSON error envelope for route-level failures.

Changes:

• Introduces /v1/workspaces/{ws}/triggers CRUD + /{id}:fire router and wires it into the FastAPI app lifespan (shared SelectorEvaluator, Dispatcher construction/injection).
• Adds an optional SubscriptionReadable capability + SubscriptionStore.get() read-back adapter, plus new wire models for manual fire.
• Adds comprehensive route tests for CRUD, selector validation, dedup behavior, and RBAC presence.

Reviewed changes

Copilot reviewed 12 out of 12 changed files in this pull request and generated 13 comments.

Show a summary per file

File	Description
src/services/trigger-service/tests/test_subscriptions_routes.py	End-to-end tests for CRUD + :fire behavior over in-memory backend and fake workflow client.
src/services/trigger-service/src/custos_trigger/stores/subscriptions.py	Adds SubscriptionStore.get() and explicit error for backends without read support.
src/services/trigger-service/src/custos_trigger/stores/base.py	Introduces SubscriptionReadable Protocol as an optional read capability.
src/services/trigger-service/src/custos_trigger/stores/init.py	Re-exports new store capability + error type.
src/services/trigger-service/src/custos_trigger/models.py	Adds ManualFireRequest / ManualFireResult wire models.
src/services/trigger-service/src/custos_trigger/dependencies.py	Adds dependency getters for dispatcher, selector evaluator, and subscription store.
src/services/trigger-service/src/custos_trigger/app.py	Wires Problem+JSON handlers + subscriptions router; builds shared evaluator and dispatcher in lifespan.
src/services/trigger-service/src/custos_trigger/api/routes/subscriptions.py	Implements REST CRUD + :fire logic (validate selector, match, dispatch, dedup).
src/services/trigger-service/src/custos_trigger/api/routes/init.py	Exports the subscriptions router.
src/services/trigger-service/src/custos_trigger/api/errors.py	Adds RFC7807 Problem+JSON envelope + exception handlers for TriggerError and validation errors.
src/services/trigger-service/src/custos_trigger/api/init.py	Exposes API utilities (ProblemDetail, handler registration).
design/components/trigger-service/todos.md	Marks TS-IMPL-015 as completed.

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