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]>

crates/tc-runtime/src/events.rs

@@ -30,6 +30,18 @@ pub enum RunEventBody {
         status: String,
         output: Value,
     },
+    /// A gated action awaits human review (§15): carries the exact preview
+    /// of what will execute, surfaced as the approval card (§10).
+    ApprovalRequired {
+        approval_id: Uuid,
+        category: String,
+        action_type: String,
+        preview: Value,
+    },
+    /// The run is blocked until the pending approval is decided.
+    RunSuspended {
+        approval_id: Uuid,
+    },
     RunCompleted {
         message_id: String,
     },
@@ -46,6 +58,8 @@ impl RunEventBody {
             RunEventBody::TextDelta { .. } => "text_delta",
             RunEventBody::StepStarted { .. } => "step_started",
             RunEventBody::StepFinished { .. } => "step_finished",
+            RunEventBody::ApprovalRequired { .. } => "approval_required",
+            RunEventBody::RunSuspended { .. } => "run_suspended",
             RunEventBody::RunCompleted { .. } => "run_completed",
             RunEventBody::Error { .. } => "error",
         }