feat(android): implement private Rust storage runtime (#90)

docs/android/parity.md

@@ -6,10 +6,12 @@ apple/Sources/AutoFill/CredentialProviderViewController.swift, crates/apple/src/
 and crates/storage/src/mobile*.rs. See [architecture.md](architecture.md) for
 support, dependency, security and update policy.
 
-**Status:** all Android implementation rows below are pending. No Android app
-exists at this decision. The table is a complete assignment of work, not a
-claim of completed parity. #111 must attach screen/component/test evidence to
-each row. Every issue linked here belongs to milestone 23.
+**Status:** #88 records the architecture baseline. The Android shell (#89),
+native packaging (#92), shared contract (#91), and private runtime (#90) are
+implemented; feature presentation rows remain assigned below. Issue comments
+record per-issue validation and outstanding test gaps. #111 must attach the
+final screen/component/test evidence to each row before claiming full parity.
+Every issue linked here belongs to milestone 23.
 
 ## Current iPhone and shared-mobile capabilities