feat(about): fall back to pinned bundle info; show runtime versions

[nmrenyi]

Summary

About page used to silently show "Bundle metadata is not available on this device yet" whenever the deployment receipt (rag_bundle_deployed.json) was missing — even when the bundle is healthy and retrieval works. This commonly affects tablets provisioned before the receipt-writing code was added to the in-app downloader.

This PR makes the page useful even in that state, and surfaces the runtime versions someone debugging on-device behaviour usually needs.

Changes

Bundle card

• Try getDeployedRagBundleInfo first; on null, fall back to getPinnedRagBundleInfo (reads rag_assets.lock.json from the APK's assets).
• Fallback rendering tags itself with an italic note ("Pinned in this build; deployment receipt not found on device.") — explicit so we don't claim the bundle is verifiably deployed when we only have build-time info.

New Runtime card

• App version (versionName (versionCode))
• LiteRT-LM version (new BuildConfig.LITERTLM_VERSION, kept in sync with the Gradle dependency via a single litertlmVersion constant)
• Configured LLM backend (GPU/CPU per BuildConfig.USE_GPU_FOR_LLM)
• Wired through a new getRuntimeInfo MethodChannel handler in MainActivity.kt.

Backend wiring

• MainActivity.kt — new getRuntimeInfo case + private method.
• build.gradle.kts — single litertlmVersion = "0.11.0" constant used both in the dependency declaration and as BuildConfig.LITERTLM_VERSION.

Localization

• New keys in both app_en.arb and app_sw.arb:
  • aboutKnowledgeBundlePinnedNote
  • aboutRuntimeTitle
  • aboutRuntimeAppLabel
  • aboutRuntimeLitertlmLabel
  • aboutRuntimeBackendLabel
• ⚠️ Swahili strings are English placeholders — need translation in a follow-up; flagged here so reviewers don't miss it.

Tested on device

• OPPO Snapdragon 8 Elite, with no rag_bundle_deployed.json on disk.
• About page renders bundle version from the pinned source with the italic note.
• Runtime card shows App: 0.1.0 (1), LiteRT-LM: 0.11.0, LLM backend: GPU.
• Retrieval + generation continue to work normally during/after viewing the page.

Test plan

• Build APK and install on a tablet that does have a rag_bundle_deployed.json — verify the bundle card shows Deployed: <timestamp> and no italic pinned-note appears (deployed path is preferred).
• Build APK and install on a tablet without a receipt — verify the italic note is shown.
• Verify Swahili locale shows the new fields (currently English text) and decide whether to follow up with proper translations.

🤖 Generated with Claude Code

[Copilot]

Pull request overview

Adds a more useful About page by falling back to pinned RAG bundle metadata when deployment receipt metadata is missing, and adds runtime/build information for on-device debugging.

Changes:

• Falls back from deployed bundle metadata to pinned APK bundle metadata.
• Adds a Runtime card showing app, LiteRT-LM, and backend information.
• Wires Android MethodChannel/runtime BuildConfig fields and localization strings.

Reviewed changes

Copilot reviewed 8 out of 8 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
app/lib/screens/about_page.dart	Adds pinned bundle fallback and Runtime info card UI.
app/lib/l10n/app_en.arb	Adds English strings for pinned note and Runtime card labels.
app/lib/l10n/app_sw.arb	Adds Swahili-locale placeholder strings for new About labels.
app/lib/l10n/app_localizations.dart	Adds generated localization getters.
app/lib/l10n/app_localizations_en.dart	Adds English localization implementations.
app/lib/l10n/app_localizations_sw.dart	Adds Swahili localization implementations.
app/android/app/src/main/kotlin/com/example/app/MainActivity.kt	Adds getRuntimeInfo MethodChannel handler.
app/android/app/build.gradle.kts	Centralizes LiteRT-LM version and exposes it via BuildConfig.

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.