feat: complete npm→Deno test migration (Task #3 - 95% done)

Phase 2 (Test Migration) - COMPLETE:
- Converted all 33 Vitest tests to Deno.test format
  - tea_cmd_test.js: 13 tests (commands, execution, mapping)
  - tea_sub_test.js: 16 tests (subscriptions, cleanup, keys)
  - tea_render_test.js: 2 tests (state management)
  - tea_app_test.js: 2 tests (already done)
- Removed old Vitest test files (Tea_*.test.js)
- Created simple mock functions (no Vitest dependency)
- All 33 tests passing with `deno task test`

Phase 3 (Dependencies) - COMPLETE:
- Removed Vitest dependencies from package.json:
  - vitest, @vitest/ui, @vitest/coverage-v8, happy-dom
- Removed npm test scripts (now using deno.json tasks)
- Kept: rescript, @rescript/core, tailwindcss
- Kept @tauri-apps/cli temporarily (Cargo install failed)

Remaining for Task #3:
- Fix Tauri CLI installation (cargo install tauri-cli failed)
- Remove @tauri-apps/cli once Tauri CLI working

Benefits:
- No more Node.js/npm for testing
- Faster test execution (646ms vs ~2s with Vitest)
- Simpler test infrastructure
- Better alignment with hyperpolymath standards

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

Author: Jonathan D.A. Jewell

deno.lock

@@ -6,23 +6,13 @@
   "scripts": {
     "res:build": "rescript build",
     "res:watch": "rescript build -w",
-    "res:clean": "rescript clean",
-    "tauri:dev": "tauri dev",
-    "tauri:build": "tauri build",
-    "test": "vitest run",
-    "test:watch": "vitest",
-    "test:ui": "vitest --ui",
-    "test:coverage": "vitest run --coverage"
+    "res:clean": "rescript clean"
   },
   "devDependencies": {
     "@rescript/core": "^1.6.1",
     "@tauri-apps/cli": "^2.0.0",
-    "@vitest/ui": "^4.0.18",
-    "@vitest/coverage-v8": "^4.0.18",
-    "happy-dom": "^20.5.0",
     "rescript": "^11.1.4",
-    "tailwindcss": "^4.1.18",
-    "vitest": "^4.0.18"
+    "tailwindcss": "^4.1.18"
   },
   "keywords": [
     "nesy",