Remove JS obfuscator that broke Mapbox GL map rendering

vite-plugin-obfuscator processes ALL output chunks including vendor
libraries, corrupting Mapbox GL's WebGL shader string literals via
base64 encoding and string splitting. This caused the map to render
as a blank screen in production.

Vite's built-in esbuild minification already mangles identifiers and
removes whitespace, providing sufficient code protection.

Adds regression tests to prevent re-introducing obfuscation plugins.

tests/unit/test_frontend_build_config.py

@@ -0,0 +1,46 @@
+"""Regression tests for frontend build configuration.
+
+Prevents re-introducing JS obfuscation plugins that break vendor libraries
+(e.g., Mapbox GL WebGL shaders corrupted by string encoding/splitting).
+"""
+import json
+from pathlib import Path
+
+FRONTEND_DIR = Path(__file__).resolve().parents[2] / "frontend"
+
+
+class TestViteConfig:
+    """Validate vite.config.ts doesn't contain dangerous build plugins."""
+
+    def test_no_obfuscator_plugin_in_vite_config(self) -> None:
+        """JS obfuscation breaks Mapbox GL's WebGL shaders and must not be used.
+
+        vite-plugin-obfuscator processes ALL output chunks (including vendor
+        libraries) and corrupts string literals used for WebGL shader source,
+        causing the map to render as a blank screen.
+        """
+        config = (FRONTEND_DIR / "vite.config.ts").read_text()
+        assert "obfuscat" not in config.lower(), (
+            "vite.config.ts must not use JS obfuscation plugins — "
+            "they corrupt Mapbox GL's WebGL shaders and break the map"
+        )
+
+    def test_no_obfuscator_in_package_json(self) -> None:
+        """Ensure obfuscator packages are not listed as dependencies."""
+        pkg = json.loads((FRONTEND_DIR / "package.json").read_text())
+        all_deps = {
+            **pkg.get("dependencies", {}),
+            **pkg.get("devDependencies", {}),
+        }
+        for dep_name in all_deps:
+            assert "obfuscat" not in dep_name.lower(), (
+                f"package.json must not include obfuscator packages (found {dep_name})"
+            )
+
+    def test_source_maps_disabled(self) -> None:
+        """Production builds must not emit source maps."""
+        config = (FRONTEND_DIR / "vite.config.ts").read_text()
+        assert "sourcemap: false" in config or "sourcemap:false" in config, (
+            "vite.config.ts must have sourcemap: false to prevent "
+            "shipping .map files in production"
+        )