feat: purge legacy agent hosts and land vault Chrome extension path

Retire ACP/Hermes/OpenCode surfaces and rename hermes_tools to
mnote_agent_tools so Page AI stays on Pi Lab only. Add Chrome vault
extension + extension token route, pre-release purge design, and soft-retire
legacy smokes for the small-group production cut.

rust/crates/mnote-web/browser/document-session-runtime.js

@@ -621,7 +621,9 @@ export const createDocumentSessionRuntime = (dependencies = {}) => {
 
   const conflictSourceLabel = (session) => {
     if (!session) return '';
-    if (session.lastExternalWriteSource === 'mnote-hermes-tool') {
+    const source = String(session.lastExternalWriteSource || '');
+    // 兼容历史 externalActor 名；产品面统一称 agent tool
+    if (source === 'mnote-agent-tool' || source === 'mnote-hermes-tool') {
       const runId = String(session.lastExternalWriteRunId || '').trim();
       return runId ? `agent run ${runId}` : 'agent run';
     }
@@ -1820,7 +1822,7 @@ export const createDocumentSessionRuntime = (dependencies = {}) => {
   window.addEventListener('tree:delta', handleTreeExternalChange);
   window.addEventListener('tree:resync', handleTreeExternalChange);
   window.addEventListener('mnote:page-ai-tool-write-completed', (event) => {
-    refreshDocumentSessionsFromExternalWrite(event?.detail || {}, 'mnote-hermes-tool');
+    refreshDocumentSessionsFromExternalWrite(event?.detail || {}, 'mnote-agent-tool');
   });
   window.addEventListener('mnote:local-upload-editor-save-completed', (event) => {
     applyLocalUploadEditorSave(event?.detail || {});