feat(adapters): external adapter plugin system with dynamic UI parser

- Plugin loader: install/reload/remove/reinstall external adapters
  from npm packages or local directories
- Plugin store persisted at ~/.paperclip/adapter-plugins.json
- Self-healing UI parser resolution with version caching
- UI: Adapter Manager page, dynamic loader, display registry
  with humanized names for unknown adapter types
- Dev watch: exclude adapter-plugins dir from tsx watcher
  to prevent mid-request server restarts during reinstall
- All consumer fallbacks use getAdapterLabel() for consistent display
- AdapterTypeDropdown uses controlled open state for proper close behavior
- Remove hermes-local from built-in UI (externalized to plugin)
- Add docs for external adapters and UI parser contract

ui/src/App.tsx

@@ -34,6 +34,7 @@ import { InstanceSettings } from "./pages/InstanceSettings";
 import { InstanceExperimentalSettings } from "./pages/InstanceExperimentalSettings";
 import { PluginManager } from "./pages/PluginManager";
 import { PluginSettings } from "./pages/PluginSettings";
+import { AdapterManager } from "./pages/AdapterManager";
 import { PluginPage } from "./pages/PluginPage";
 import { RunTranscriptUxLab } from "./pages/RunTranscriptUxLab";
 import { OrgChart } from "./pages/OrgChart";
@@ -175,6 +176,7 @@ function boardRoutes() {
       <Route path="inbox/new" element={<Navigate to="/inbox/mine" replace />} />
       <Route path="design-guide" element={<DesignGuide />} />
       <Route path="tests/ux/runs" element={<RunTranscriptUxLab />} />
+      <Route path="instance/settings/adapters" element={<AdapterManager />} />
       <Route path=":pluginRoutePath" element={<PluginPage />} />
       <Route path="*" element={<NotFoundPage scope="board" />} />
     </>
@@ -321,6 +323,7 @@ export function App() {
             <Route path="experimental" element={<InstanceExperimentalSettings />} />
             <Route path="plugins" element={<PluginManager />} />
             <Route path="plugins/:pluginId" element={<PluginSettings />} />
+            <Route path="adapters" element={<AdapterManager />} />
           </Route>
           <Route path="companies" element={<UnprefixedBoardRedirect />} />
           <Route path="issues" element={<UnprefixedBoardRedirect />} />