docs(governance): record product scaffolding paths (DEC-022)

Updates two documents to reflect the workspace + Flutter app
scaffold landed in the previous commit.

path-migration-map.md v0.9.2 -> v0.9.3:
  Adds §3 Implementation Path Layout. Lists each subsystem's
  canonical crate path alongside its SAD / SysDes / DEC authority.
  Notes that the Flutter app is owned by Flutter tooling and is
  not a Cargo workspace member.

CHANGELOG entry under [Unreleased]:
  - Documents the seven new Cargo workspace members and the
    invariants pinned at the workspace level.
  - Documents the Flutter app scaffold, the DEC-004 minSdk = 28
    override, and the DEC-015 English + Simplified Chinese ARB
    catalogue (with the ADR-008 server-content reaffirmation).
  - Records the empirical verification (cargo check + cargo test
    + flutter analyze + flutter test all clean).

CHANGELOG.md

@@ -8,6 +8,60 @@ This project is expected to follow a Conventional Commits style workflow.
 
 ### Added
 
+- **Product workspace scaffold (DEC-022).** Created the canonical
+  implementation directory layout per the README sketch + SAD §7.2:
+  - `Cargo.toml` — top-level Cargo workspace declaring seven members
+    and excluding the `poc/` spike trees and `apps/chanora_flutter`.
+    Pins `license = "MIT OR Apache-2.0"` (DEC-020) and
+    `rust-version = "1.95"` workspace-wide.
+  - `core/chanora_core/` — top-level Rust API + orchestration. Owns
+    `ChanoraSession` (placeholder) and the `CoreError` enum that
+    typed-wraps every subsystem error.
+  - `crates/chanora_protocol/` — tsclientlib adapter scaffold,
+    opaque `ChannelId` / `ClientId` types, `ProtocolError`.
+  - `crates/chanora_state/` — `StateError`, `ConnectionState` enum.
+  - `crates/chanora_audio/` — `AudioError`, `AudioEffects` struct
+    whose defaults match DEC-007/008/009/010 (all four effects on).
+  - `crates/chanora_storage/` — `StorageError`, marker traits for
+    the two repositories per the SAD-067 separation.
+  - `crates/chanora_diagnostics/` — `DiagnosticsError`,
+    `REDACTION_MARKER` constant matching the PoC, `Redactor` shell.
+  - `crates/chanora_bridge/` — `BridgeError` DTO (Serialize +
+    Deserialize) for FRB 2.x boundary.
+  Workspace `cargo check --workspace` and `cargo test --workspace`
+  both clean on Rust 1.95.
+- **Flutter application scaffold.**
+  - `apps/chanora_flutter/` created via `flutter create` with
+    `--org app.chanora --project-name chanora_flutter`. Platforms
+    enabled at scaffold time: Linux + Android.
+  - `apps/chanora_flutter/android/app/build.gradle.kts` overridden
+    to `minSdk = 28` per DEC-004 (raised from Flutter's default
+    minSdk by explicit owner ruling, register v0.9.5).
+  - `flutter_localizations` + `intl` added to `pubspec.yaml`;
+    `flutter.generate: true` enabled.
+  - `l10n.yaml` configured to emit `lib/l10n/generated/AppL10n`
+    (no synthetic package — `synthetic-package` was removed in
+    Flutter 3.41+).
+  - `lib/l10n/app_en.arb` — English template ARB with the MVP key
+    set (`appTitle`, `homeGreeting`, `homeNotProductionReadyBanner`,
+    `connectAction`).
+  - `lib/l10n/app_zh.arb` — Simplified Chinese translations per
+    DEC-015 (MVP language scope expanded from English-only).
+  - `lib/main.dart` and `test/widget_test.dart` rewritten as a
+    minimal scaffold that exercises both locales.
+  - `flutter analyze` reports no issues. `flutter test` runs the
+    English + Simplified Chinese smoke tests and both pass.
+
+### Changed
+
+- `docs/governance/path-migration-map.md` bumped to v0.9.3 with a
+  new §3 *Implementation Path Layout* recording the DEC-022
+  directory adoption (`apps/`, `core/`, `crates/`) and pointing
+  each subsystem at its crate alongside the relevant SAD/SysDes/DEC
+  authority.
+
+### Added (LICENSE files)
+
 - `LICENSE-APACHE` — Apache License Version 2.0 text (DEC-020).
 - `LICENSE-MIT` — MIT License text (DEC-020).
 - Initial repository foundation files.