feat: notify biolm-web on notebook changes

[ChanceChallacombe]

What this does

Adds .github/workflows/notify-notebook-sync.yml — the source-side trigger for the cross-repo notebook sync pipeline.

When content/*.ipynb files change on main, this workflow fires a notebook-sync repository_dispatch to BioLM/biolm_web. The handler there (handle-notebook-sync.yml) converts notebooks to self-contained HTML, generates a JupyterPage Django migration, and opens a bot PR. On next deploy, manage.py migrate loads the updated notebook pages into the DB.

workflow_dispatch is also supported for a full re-sync of all notebooks without needing a new commit (useful after merging the companion PR or recovering from a failed run).

---

Flow

tutorials-and-guides: push to main (content/*.ipynb changed)
        ↓
notify-notebook-sync.yml (this file)
  - git diff HEAD~1 HEAD → detect changed .ipynb files
  - repository_dispatch → BioLM/biolm_web, event: notebook-sync
    payload: { notebooks: [{filename, change_type}], source_sha }
        ↓
biolm_web: handle-notebook-sync.yml
  - Checkout biolm_web + tutorials-and-guides
  - pip install nbconvert==7.16.4 nbformat==5.10.4 beautifulsoup4
  - python scripts/convert_notebooks_to_html.py  → jupyter_html/*.html
  - python scripts/generate_jupyter_migration.py → ui/migrations/XXXX_load_synced_jupyter_pages.py
  - peter-evans/create-pull-request → bot PR on biolm_web

---

Auth

Uses the org-level APP_ID + APP_PRIVATE_KEY GitHub App secrets (same as protocol-sync and model-sync). No new secrets required.

---

Companion PR

BioLM/biolm_web #130 — adds handle-notebook-sync.yml, scripts/generate_jupyter_migration.py, and the jupyter_html/ directory. Both PRs should be merged together (or biolm_web first).

---

Fixes in latest commit (vs original PR)

• Repo name bug: BioLM/biolm-web (hyphen) → BioLM/biolm_web (underscore) in the dispatch target and app-token repositories: field. The hyphenated name would have silently failed — GitHub would return a 404 on dispatch.
• Concurrency block: added cancel-in-progress: true to match all other sync workflows in the pipeline.