Feature request: official @perryts/app-group for cross-process shared storage

[proggeramlug]

Feature request: official @perryts/app-group for cross-process shared storage

Widget extensions, share extensions, watchOS targets, and the main app all need a way to share data with the host app. iOS does this through App Groups — a file-system + UserDefaults sandbox shared between targets that share an application-groups entitlement. Android has the same problem with MODE_MULTI_PROCESS SharedPreferences or content providers.

There's no official Perry binding for this yet, so apps roll a local fork (e.g. our perry-searchbird-shared).

Surface we'd expect

// @perryts/app-group — TS surface
export declare function js_app_group_set(key: string, value: string): void;
export declare function js_app_group_get(key: string): string;          // "" if absent
export declare function js_app_group_delete(key: string): void;
export declare function js_app_group_write_blob(path: string, data: string): void;  // path relative to group root
export declare function js_app_group_read_blob(path: string): string;

Configuration:

[ios]
app_group = "group.io.example.app"   # must match entitlement

[android]
shared_prefs_name = "io.example.app.shared"

Notes:

• iOS / macOS: UserDefaults(suiteName: <appGroup>) for kv, FileManager.default.containerURL(forSecurityApplicationGroupIdentifier:) for blobs.
• Android: scoped SharedPreferences keyed by shared_prefs_name.
• Linux/Windows: stub to a per-user XDG path ($XDG_DATA_HOME/<bundle_id>/shared/).
• Entitlement plumbing: Perry's signing pipeline already merges entitlements from perry.toml; application-groups should drop in cleanly.

Why this matters

Without this, the only official way to wire a Perry app to a Perry-built widget is to hand-write a Rust+Swift bridge per project. That's a steep onboarding cliff and creates a forest of subtly-different forks across the ecosystem.