Add functional test coverage and combined test runner

README.md

@@ -60,6 +60,19 @@ zig build run
 zig build -Doptimize=ReleaseFast
 ```
 
+## Testing
+
+```bash
+# Frontend functional/unit coverage
+npm --prefix frontend run test:run
+
+# Backend Zig coverage
+zig build test
+
+# Run both test suites
+./tests/run-functional-tests.sh
+```
+
 ### Package as macOS App
 
 ```bash

build.zig

@@ -41,11 +41,12 @@ pub fn build(b: *std.Build) void {
     // Tests
     const unit_tests = b.addTest(.{
         .root_module = b.createModule(.{
-            .root_source_file = b.path("src/main.zig"),
+            .root_source_file = b.path("src/test_main.zig"),
             .target = target,
             .optimize = optimize,
         }),
     });
+    unit_tests.linkSystemLibrary("util");
     unit_tests.linkSystemLibrary("sqlite3");
     unit_tests.linkLibC();