P2 BLOCKING exit green: approval interception chain end-to-end

- tc-tools: Effect declarations -> §15 GatedCategory mapping, deny-by-default
  external reach, taint invariant property-tested (tainted external effects
  are NEVER auto-allowed)
- tc-safety: pending approvals with exact payload+preview, CAS decide with
  audit + single-use grant in one tx, checkpoint suspend/load, exclusive
  resume claim, expiry sweep, decided-unresumed work queue (migration 0004
  adds the outbox the gated email.send tool writes)
- tc-runtime: resumable LoopState checkpointed to agent_runs; gated tool ->
  approval row -> approval_required/run_suspended events -> suspend; resume
  consumes the grant BEFORE executing (spent grant = no execution), rejection
  feeds a structured refusal in-band; durable resume sweeper; continuous
  journal seq across suspension (tested). ContentPart::Text became a struct
  variant — internally-tagged newtype primitives don't serialize
- tc-api: GET/decide approvals endpoints (409 double-decide, tenant
  isolation), decision triggers in-process resume; full chain proven over
  HTTP incl. gateway resumeFrom continuation
- frontend: approval_required/run_suspended events, suspended reply state,
  inline ApprovalCard (§10: summary, category, exact payload preview,
  approve/reject -> decide + stream re-attach), /approvals queue page, nav
- E2E (14 journeys, workers:1 to serialize the shared backend): gated email
  blocks with disabled composer -> approve -> continuation + ✓ step + reload
  replay; reject -> ✗ step, nothing executed; queue page decides pending

106 Rust + 61 frontend tests + 14 Playwright journeys green.

Co-Authored-By: Claude Fable 5 <[email protected]>

.sqlx/query-0da90e00e009575f8570de01d2ee0e7cbd6cea8605b331b44a96049e361e378c.json

@@ -0,0 +1,16 @@
+{
+  "db_name": "PostgreSQL",
+  "query": "INSERT INTO execution_grants (id, approval_id, nonce)\n             VALUES ($1, $2, $3)",
+  "describe": {
+    "columns": [],
+    "parameters": {
+      "Left": [
+        "Uuid",
+        "Uuid",
+        "Text"
+      ]
+    },
+    "nullable": []
+  },
+  "hash": "0da90e00e009575f8570de01d2ee0e7cbd6cea8605b331b44a96049e361e378c"
+}