#55 build: upgrade AI stack and dependency tooling

Summary

• upgrade the AI SDK, Convex, React ecosystem, TanStack, Vite, and supporting dependencies
• migrate runtime integrations for AI SDK v7, Composio, React DayPicker, and updated generated Convex types
• harden message sanitization, tool caching, provider errors, and type boundaries
• replace heavyweight provider icons with local SVGs and keep the Kimi mark visible while inactive
• add Dependabot, dependency verification CI, and official Convex AI guidance and skills

Why

Keeps the application on current supported APIs, removes obsolete dependencies and unsafe type assertions, fixes the Kimi model-selector icon regression, and automates future dependency verification.

Validation

• bun run format:check
• bun run lint:check
• bun run typecheck
• bun run test — 76 files, 1,122 tests passed
• bun run build
• bun audit — no vulnerabilities found

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Summary by cubic

Upgraded the AI stack and tooling, installed official Convex AI guidance and skills, and isolated and finalized Composio agent sessions to improve reliability while tightening message handling and provider UI.

• Dependencies

  • Bumped @ai-sdk/* to v4 and migrated APIs (isStepCount, generateImage, toUIMessageStream, GoogleLanguageModelOptions).
  • Updated convex ecosystem and added managed AI guidelines and agent skills.
  • Refreshed React/TanStack/Vite; added @rolldown/plugin-babel.
  • Added Dependabot and dependency checks CI (format, lint, types, tests, build, bun audit).

• Refactors

  • Isolated Composio agent sessions and ensured they are finalized with clear outcomes; removed Redis tool cache, updated routes, and added session tests.
  • Added support and redaction for reasoning-file parts across sanitization, detectors, and UI.
  • Replaced heavy provider icons with local SVGs and standardized type checking and docs to tsc; enforced typed Vitest mocks.