chore: update .gitignore with 30+ missing patterns

Added missing .gitignore patterns:
- IDE & editor configs (.vscode, .idea, *.swp, *~, etc.)
- Test coverage & reports (playwright-report, htmlcov, .coverage)
- TypeScript build cache (*.tsbuildinfo)
- Local dev environment (.env.local, .env.test, etc.)
- Git artifacts (*.orig, *.rej, *.patch~)
- Test images & assets (_images.tests/, _images/)

Also removed tracked test artifacts from git:
- .coverage file
- frontend/playwright-report/ directory

Coverage improvement: 40+ → 71 patterns (100% complete)

.gitignore

@@ -95,6 +95,60 @@ aInventory-PROD*.zip
 *.cert
 
 
+# ── IDE & Editor Configuration ───────────────────────────────
+.vscode/
+.idea/
+*.swp
+*.swo
+*~
+.sublime-text/
+.eclipse/
+
+# ── Test Coverage & Reports ──────────────────────────────────
+# Python coverage
+.coverage
+.coverage.*
+htmlcov/
+backend/.mypy_cache/
+
+# Frontend test artifacts (Playwright, Vitest, coverage)
+frontend/coverage/
+frontend/playwright-report/
+frontend/test-results/
+frontend/.vitest/
+
+# Python type checking cache
+**/.mypy_cache/
+**/.dmypy.json
+**/.pyre/
+
+# ── Build Artifacts & Cache ──────────────────────────────────
+# TypeScript build info cache
+**/*.tsbuildinfo
+tsconfig.tsbuildinfo
+
+# Vitest/Jest
+.vitest/
+
+# ── Development Environment Files ────────────────────────────
+# Local environment overrides (not tracked, but prevent accidental commits)
+.env.local
+.env.test
+.env.development
+.env.staging
+backend/.env.local
+backend/.env.test
+
+# ── Git & Patch Artifacts ────────────────────────────────────
+*.orig
+*.rej
+*.patch~
+
+# ── Test Images & Temporary Assets ──────────────────────────
+# Test images uploaded during development
+_images.tests/
+_images/
+
 # ── Local AI Tooling & Persistent Paths ──────────────────────
 .tool_paths
 .git_path