Auto-update formulae when new versions are published to PyPI

## Background

This tap will host two categories of formulae:

1. **First-party** — projects owned by get2knowio (e.g. `climax-mcp`), where the publish workflow lives in our own repos and we can trigger cross-repo events
2. **Third-party** — formulae for external projects where we have no control over the publish pipeline

Each category needs a different update strategy.

## First-party formulae (e.g. `climax-mcp`)

Use `repository_dispatch` for immediate, event-driven updates:

- In the app repo's publish workflow, after pushing to PyPI, fire a `repository_dispatch` event to this tap repo passing the new version
- This tap listens for that event, runs `brew update-python-resources` to regenerate resource blocks, commits, and pushes
- Requires a PAT with `repo` scope stored as a secret in each app repo

## Third-party formulae

Use a scheduled workflow that polls PyPI:

- Run hourly (or daily) via cron
- For each third-party formula, fetch `https://pypi.org/pypi//json` and compare latest version to what's in the formula
- If a new version is detected, run `brew update-python-resources` and open a PR (rather than committing directly, so there's a chance to review/test before merging)

## Implementation notes

- `brew update-python-resources Formula/.rb` handles regenerating all transitive dependency resource blocks automatically — the workflow just needs to bump the top-level `url` and `sha256` first
- Both strategies should open a PR rather than push directly to `main`, so the bottling CI (see #1) can run and attach bottles before merge
- The third-party polling workflow should be idempotent — skip cleanly if the formula is already at the latest version