[JolandaVerhoef]

Overview

This PR continues the evolution of JetPacker following the Android Dev Summit '26:

1. Production Evolution & On-Device Assistant:

   • Updates TravelAssistantViewModel to dynamically query live Room database trips (tripDao.getAllTrips()) instead of hardcoded demo trip presets.
   • Configures on-device Gemini Nano v4 Preview via public ML Kit GenAI Agent (ModelReleaseStage.PREVIEW, ModelPreference.FAST) with automatic status checks and on-device model download handling.
   • Prunes tool descriptions and schemas in TravelDaoTools, saving ~1,200 tokens per inference turn on on-device context window budgets.
   • Enhances local fallback and transaction highlighting for expenses and budget status queries.

2. Persistent Trips, Budget & Itinerary Scheduling:

   • Adds persistent budget tracking and currency selection to trip creation and editing panels.
   • Adds scheduled timeline events support with date/time parsing.
   • Updates ManageExpensesViewModel and ItineraryViewModel with persistent database integration.

3. Architecture Documentation & Developer Ergonomics:

   • Adds ARCHITECTURE.md documenting subsystem layout, module graph, Room database v4 schema, and hybrid on-device / cloud AI architecture.
   • Adds AGENTS.md and workspace development skill providing build, test, and style guidelines (UDF, no FQCN, Hilt injection constraints).
   • Sanitizes deployment scripts, README instructions, and server config placeholders.

Verification

• Unit test suite verified green: ./gradlew testDebugUnitTest (494 tasks executed, 0 failures).