chore: GitHub Actions CI workflow

Two parallel jobs:
- test: pytest on Windows + Linux matrix. Installs the minimal deps the
  tests actually exercise (pyyaml + openai + flet). Heavy STT/TTS/Vosk
  packages are runtime concerns, tests don't touch them.
- lint: ruff on Linux, lenient ruleset — catches real errors (E, F, W)
  without enforcing stylistic preferences the codebase wasn't written
  with ruff in mind for. Non-blocking (|| true) so style nits don't
  break CI.

Triggers on push to feature/pc-tools/master/main and PRs to master/main.

.github/workflows/ci.yml

@@ -0,0 +1,57 @@
+# CI for J.A.R.V.I.S. Python fork.
+#
+# Two jobs in parallel:
+#   - test:  pytest on the in-repo test suite. Only installs the minimal
+#            dependencies the tests actually touch (yaml, openai for
+#            llm_backend, flet for the GUI smoke tests). Heavy STT / TTS / Vosk
+#            packages aren't needed in CI — they're runtime concerns, and the
+#            tests are written to not touch them.
+#   - lint:  ruff against the project. Style problems should be caught here
+#            before they land in master.
+#
+# Cross-platform: tests run on both Windows and Linux runners to catch path
+# / line-ending / fs-case issues early.
+
+name: Python CI
+
+on:
+  push:
+    branches: [feature/pc-tools, master, main]
+  pull_request:
+    branches: [master, main]
+
+jobs:
+  test:
+    name: pytest (${{ matrix.os }})
+    strategy:
+      fail-fast: false
+      matrix:
+        os: [windows-latest, ubuntu-latest]
+    runs-on: ${{ matrix.os }}
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions/setup-python@v5
+        with:
+          python-version: '3.11'
+          cache: 'pip'
+      - name: Install test deps
+        run: |
+          python -m pip install --upgrade pip
+          pip install pytest pyyaml openai flet
+      - name: Run tests
+        run: pytest tests/ -v --tb=short
+
+  lint:
+    name: ruff
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions/setup-python@v5
+        with:
+          python-version: '3.11'
+      - name: Install ruff
+        run: pip install ruff
+      - name: Lint
+        # Drop the strictest rules — the codebase wasn't written with ruff in
+        # mind and we don't want CI to fail on stylistic preferences.
+        run: ruff check --select=E,F,W --ignore=E501,F401,E402,W291,W293,W391 . || true