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]>

frontend/src/components/chat/ChatWorkspace.tsx

@@ -33,7 +33,7 @@ export function ChatWorkspace({
   sessions,
 }: ChatWorkspaceProps) {
   const router = useRouter();
-  const { state, send } = useChat(agent.id, sessionKey, initialMessages);
+  const { state, send, decide } = useChat(agent.id, sessionKey, initialMessages);
   const [draft, setDraft] = useState("");
   const [{ sessions: showSessions }] = useQueryStates(panelParsers, {
     shallow: true,
@@ -74,7 +74,7 @@ export function ChatWorkspace({
         {state.messages.length === 0 ? (
           <WelcomeState agent={agent} onPick={setDraft} />
         ) : (
-          <MessageList messages={state.messages} agent={agent} />
+          <MessageList messages={state.messages} agent={agent} onDecide={decide} />
         )}
         <Composer
           agentName={agent.name}