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/src/app.rs

@@ -1,4 +1,3 @@
-use crate::acp_runtime::AcpRuntimeManager;
 use crate::document_buffer_store::BufferStore;
 use crate::editor_actor::EditorRuntimeActor;
 use crate::local_folder_watcher_registry::LocalFolderWatcherRegistry;
@@ -33,7 +32,6 @@ pub struct AppConfig {
     pub enable_debug_shell_routes: bool,
     pub enable_editor_actor: bool,
     pub enable_page_ai_pi_lab: bool,
-    pub hermes_base_path: String,
     pub compat_next_base_path: String,
     pub convex_url: Option<String>,
     pub convex_admin_key: Option<String>,
@@ -67,8 +65,6 @@ impl AppConfig {
                 .unwrap_or(false),
             enable_editor_actor: env_bool("MNOTE_WEB_ENABLE_EDITOR_ACTOR", true),
             enable_page_ai_pi_lab: env_bool("MNOTE_PAGE_AI_PI_LAB", true),
-            hermes_base_path: env::var("MNOTE_WEB_HERMES_BASE_PATH")
-                .unwrap_or_else(|_| "/api/hermes".into()),
             compat_next_base_path: env::var("MNOTE_WEB_COMPAT_NEXT_BASE_PATH")
                 .unwrap_or_else(|_| "/api/compat/next".into()),
             convex_url: None,
@@ -163,7 +159,6 @@ pub struct AppState {
     pub editor_actor: EditorRuntimeActor,
     pub block_delta_tx: broadcast::Sender<serde_json::Value>,
     pub stream_delta_tx: broadcast::Sender<serde_json::Value>,
-    pub acp_runtime: Arc<AcpRuntimeManager>,
     pub buffer_store: BufferStore,
     control_plane: Arc<dyn ControlPlaneStore>,
 }
@@ -185,7 +180,6 @@ impl AppState {
             editor_actor: actor,
             block_delta_tx,
             stream_delta_tx,
-            acp_runtime: Arc::new(AcpRuntimeManager::from_env()),
             buffer_store,
             control_plane,
         }
@@ -389,7 +383,6 @@ mod tests {
             enable_debug_shell_routes: false,
             enable_editor_actor: true,
             enable_page_ai_pi_lab: true,
-            hermes_base_path: "/api/hermes".into(),
             compat_next_base_path: "/api/compat/next".into(),
             convex_url: None,
             convex_admin_key: None,