wip(13-08): checkpoint before operator session restart — Task 1 GREEN (28/28), Task 2 in progress

Executor stopped deliberately for a session restart (bypass-permissions relaunch).
Executor's final report: 'cargo test assistant confirm-gate suite 28/28 green,
individual nonce test passes; committing Task 1 next — first verify the
tools.rs/grants.rs/backends diffs are formatting-only.'

Task 1 (D-07/D-11 confirm gate, backend) is implemented and test-green but this
checkpoint is verbatim-uncommitted-state, NOT the reviewed atomic Task 1 commit:
continuation executor should verify diffs, then reset --soft or commit-on-top
into proper feat(13-08) task commits. Task 2 (ToolConfirmModal.vue trusted
chrome, Chat.vue + contextBroker.ts wiring) is partially built, tests written.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

core/archipelago/src/assistant/backends/mod.rs

@@ -21,7 +21,12 @@ pub enum BackendTurn {
 
 #[async_trait]
 pub trait Backend: Send + Sync {
-    async fn send(&self, system: &str, tools: &[ToolDef], history: &[ChatMessage]) -> Result<BackendTurn>;
+    async fn send(
+        &self,
+        system: &str,
+        tools: &[ToolDef],
+        history: &[ChatMessage],
+    ) -> Result<BackendTurn>;
 }
 
 /// D-04's backend chain: local Ollama first (node data never leaves the