fix: remove conflicting tree-sitter-go and tree-sitter-python dependencies

These grammars require tree-sitter@^0.25.0 but we use 0.21.1.
They already failed at runtime with try/catch graceful fallback.
Removing them fixes npm peer dependency conflict during pi install.

- Remove tree-sitter-go and tree-sitter-python from dependencies
- ast-extract.ts already handles missing grammars gracefully
- Heuristics + LLM layer cover Go/Python analysis anyway

package.json

@@ -46,8 +46,6 @@
     "p-limit": "^7.3.0",
     "picocolors": "^1.1.1",
     "tree-sitter": "^0.21.0",
-    "tree-sitter-go": "^0.25.0",
-    "tree-sitter-python": "^0.25.0",
     "tree-sitter-typescript": "^0.21.0"
   }
 }