feat: Gemini AI integration — conversations, messages, image gen

- Fixed YAML parse error (unquoted colon in description broke @scalar/json-magic)
- Converted orval.config.ts → orval.config.cjs (fixes orval v8 TypeScript config loading)
- Codegen now works: zod schemas + React Query hooks regenerated with Gemini types
- Added Gemini tag, 4 path groups, 8 schemas to openapi.yaml
- lib/integrations-gemini-ai wired: tsconfig refs, api-server package.json dep
- Created routes/gemini.ts: CRUD conversations/messages + SSE chat stream + image gen
- Mounted /gemini router in routes/index.ts

lib/integrations-gemini-ai/tsconfig.json

@@ -0,0 +1,12 @@
+{
+  "extends": "../../tsconfig.base.json",
+  "compilerOptions": {
+    "composite": true,
+    "declarationMap": true,
+    "emitDeclarationOnly": true,
+    "outDir": "dist",
+    "rootDir": "src",
+    "types": ["node"]
+  },
+  "include": ["src"]
+}