feat(FN-3398): update desktop README with multi-project setup and troublesh

The merge lands Step 7 of FN-3398, adding documentation and delivery artifacts across the mobile and desktop packages with updated READMEs, mobile-specific docs, and architecture references.

Fusion-Task-Id: FN-3398

packages/mobile/src/plugins/native-shell.ts

@@ -0,0 +1,82 @@
+import type {
+  FusionShellApi,
+  ShellConnectionProfile,
+  ShellConnectionProfileInput,
+  ShellConnectionState,
+} from "../types.js";
+import {
+  deleteShellProfile,
+  listShellProfiles,
+  loadShellProfiles,
+  saveShellProfile,
+  setActiveShellProfile,
+} from "./connection-profiles.js";
+import { QrScanner, type QrScanResult } from "./qr-scanner.js";
+
+type Listener = (state: ShellConnectionState) => void;
+
+export class MobileNativeShellBridge implements FusionShellApi {
+  private listeners = new Set<Listener>();
+
+  constructor(private readonly qrScanner: QrScanner = new QrScanner()) {}
+
+  private async buildState(): Promise<ShellConnectionState> {
+    const persisted = await loadShellProfiles();
+    return {
+      host: "mobile-shell",
+      activeProfileId: persisted.activeProfileId,
+      profiles: persisted.profiles,
+    };
+  }
+
+  private async emitState(): Promise<ShellConnectionState> {
+    const state = await this.buildState();
+    for (const listener of this.listeners) {
+      listener(state);
+    }
+    return state;
+  }
+
+  getState(): Promise<ShellConnectionState> {
+    return this.buildState();
+  }
+
+  listProfiles(): Promise<ShellConnectionProfile[]> {
+    return listShellProfiles();
+  }
+
+  async saveProfile(profile: ShellConnectionProfileInput): Promise<ShellConnectionProfile> {
+    const saved = await saveShellProfile(profile);
+    await this.emitState();
+    return saved;
+  }
+
+  async deleteProfile(profileId: string): Promise<void> {
+    await deleteShellProfile(profileId);
+    await this.emitState();
+  }
+
+  setActiveProfile(profileId: string | null): Promise<ShellConnectionState> {
+    return setActiveShellProfile(profileId).then(() => this.emitState());
+  }
+
+  setDesktopMode(): Promise<ShellConnectionState> {
+    return Promise.reject(new Error("Desktop mode is not supported in mobile shell"));
+  }
+
+  startQrScan(): Promise<QrScanResult> {
+    return this.qrScanner.scanConnection();
+  }
+
+  async openConnectionManager(): Promise<void> {
+    // Handled by dashboard shell context state.
+  }
+
+  subscribe(listener: Listener): () => void {
+    this.listeners.add(listener);
+    void this.getState().then(listener);
+    return () => {
+      this.listeners.delete(listener);
+    };
+  }
+}