Refactor application path handling and data storage architecture

Replace simple directory-based path system with git-aware data management that uses global data directories and proper workspace detection.

🤖 Generated with opencode
Co-Authored-By: opencode <noreply@opencode.ai>

packages/opencode/src/global/index.ts

@@ -17,4 +17,8 @@ export namespace Global {
   export function cache() {
     return paths.cache
   }
+
+  export function data() {
+    return paths.data
+  }
 }