WIP: Gemini CLI extension infrastructure

Add experimental Gemini CLI extension with MCP server that exposes
skills as individual tools. Infrastructure works but auto-triggering
skills is blocked by Gemini CLI treating context files as advisory
rather than executable instructions.

See issue #128 for detailed findings.

- gemini-extension.json manifest
- MCP server with individual skill tools
- GEMINI.md bootstrap attempts (don't work)
- Installation documentation

.gemini/mcp-server/tsconfig.json

@@ -0,0 +1,16 @@
+{
+  "compilerOptions": {
+    "target": "ES2022",
+    "module": "NodeNext",
+    "moduleResolution": "NodeNext",
+    "outDir": "dist",
+    "rootDir": "src",
+    "strict": true,
+    "esModuleInterop": true,
+    "skipLibCheck": true,
+    "forceConsistentCasingInFileNames": true,
+    "declaration": true
+  },
+  "include": ["src/**/*"],
+  "exclude": ["node_modules", "dist"]
+}