Launch conversational expense entry with usage monitoring

[PengfanZ]

What changed

• launches the reviewed text and voice conversational expense-entry flows while keeping manual entry first
• adds privacy-safe, event-name-only funnels for text and voice requests, ready drafts, clarifications, and failures
• adds the Supabase migration, Home report query, changelog copy, production Edge Function deployment step, and release documentation
• keeps prompts, audio, names, IDs, descriptions, amounts, draft counts, model output, and latency out of analytics

Production prerequisite

Before merge, configure the production Supabase Edge Function secrets documented in docs/DEPLOYMENT.md, especially OPENROUTER_API_KEY and AI_EXPENSE_ENABLED=true. The production GitHub environment already has VITE_AI_EXPENSE_ENABLED=true.

Validation

• TypeScript typecheck
• ESLint with zero warnings
• 489 Vitest tests with 100% statement, branch, function, and line coverage
• fresh local Supabase migration rebuild plus 153 pgTAP contracts
• 12 stable Playwright flows and 14 AI Playwright flows
• AI-enabled GitHub Pages production build
• preview database migration, real recorder query, and cleanup
• Supabase security and performance advisor review