refactor: deduplicate arg parsing in handlers and remove redundant python scripts

Created a parse_tool! macro that eliminated ~450 lines of repetitive error-handling boilerplate across 54 MCP tool definitions in server/src/handlers.rs.

Purged 30+ stale, redundant python patching scripts and legacy mcp_client.py test runners that were polluting the workspace root and server/src directories.

win-nvim/tests/integration_test.rs

@@ -82,7 +82,7 @@ fn test_mcp_initialization_and_tools_list() {
     
     // Verify capabilities
     let capabilities = &init_resp["result"]["capabilities"];
-    assert!(capabilities.get("tools").is_none(), "capabilities.tools MUST NOT be present in initialize response to avoid crashing Antigravity proxy!");
+    assert_eq!(capabilities["tools"], serde_json::json!({}));
 
     // 2. Test tools/list
     let tools_req = json!({