feat(v1.4.0): CSV/Excel/JSON/NextUp exports + hybrid smart year standing

- Export modules (export-csv/json/xlsx) mirroring the PDF layout, plus a
  Next Up import CSV matching the raycast/nextup column contract.
- Hybrid Year Level: View Grades history (exact per-semester standing),
  falling back to units math (prospectus total - lacking), then profile.
  Popup adds a year-mode setting (auto/custom/off).
- On-page button row now offers PDF / CSV / Excel / JSON / Next Up.
- Bump version to 1.4.0.
- Tag-only build workflow with an optional AMO sign step for a signed .xpi;
  separate ci.yml keeps tests on pushes/PRs.
- Tests: year-standing parser tests + export tests (CSV quoting, JSON schema,
  XLSX structure); CI validates XLSX via openpyxl.

.gitea/workflows/ci.yml

@@ -0,0 +1,35 @@
+name: ci
+
+# Fast test feedback on daily development. No builds, no releases — those only
+# happen on v* tags via build.yml.
+on:
+  push:
+    branches: [feat/ismis-helper, prod]
+  pull_request:
+
+jobs:
+  test:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Set up Node
+        uses: actions/setup-node@v4
+        with:
+          node-version: 20
+
+      - name: Install dev dependencies
+        run: npm ci || npm install
+
+      - name: Install PyMuPDF + openpyxl (PDF text + XLSX validation)
+        run: |
+          python3 -m venv /tmp/venv
+          /tmp/venv/bin/pip install --quiet pymupdf openpyxl
+          echo "/tmp/venv/bin" >> "$GITHUB_PATH"
+
+      - name: Run tests
+        run: npm test
+
+      - name: Validate exports open in real readers
+        run: node scripts/validate-exports.js