feat(wasm,ext): org_manifest_decrypt/encrypt over WASM + faithful OrgManifest TS mirror

- Add `org_manifest_decrypt` + `org_manifest_encrypt` to relicario-wasm/src/lib.rs,
  placed after `org_unwrap_key`; mirror the existing manifest_decrypt/manifest_encrypt
  pattern exactly (need_key guard, session::with, js_value_for). Core import path:
  relicario_core::decrypt_org_manifest / relicario_core::encrypt_org_manifest (crate root).
- Add round-trip test `org_manifest_round_trip_via_handle` in org_tests: encrypt via
  WASM wrapper, decrypt via core directly (avoids serde_wasm_bindgen off-wasm).
  Asserts collection/title/tags/schema_version survive the round-trip; asserts nonce
  uniqueness. TDD: RED (compile error) → GREEN confirmed.
- Declare org_manifest_decrypt/org_manifest_encrypt in extension/src/wasm.d.ts.
- Add faithful/lean OrgManifestEntry + OrgManifest TS interfaces to
  extension/src/shared/types.ts: {id, type, title, tags[], modified, trashed_at?,
  collection} — no personal-only fields; collection required. Mirrors org.rs:184-202.
- Plan-doc: rewrite Task 2 body (re-scope rationale + checked steps), fix File
  Structure + Architecture lines, amend Hand-off contract (org_list_items ->
  OrgManifestEntry[]; org items remain personal Item).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_014s527M917W47LDrfQ4t47g

extension/src/wasm.d.ts

@@ -88,6 +88,8 @@ declare module 'relicario-wasm' {
   export function wasm_unwrap_recovery_qr(payload_b64: string, passphrase: string): Uint8Array;
 
   export function org_unwrap_key(keys_blob: Uint8Array, device_private_openssh: string): SessionHandle;
+  export function org_manifest_decrypt(handle: SessionHandle, encrypted: Uint8Array): unknown;
+  export function org_manifest_encrypt(handle: SessionHandle, manifest_json: string): Uint8Array;
 
   export default function init(module_or_path?: unknown): Promise<void>;
   export function initSync(args: { module: WebAssembly.Module }): void;