[PD1-138] Standardize Continuous Integration workflow

## Why

The Dependabot review-and-merge automation we run in `ui` reacts to CI through a `workflow_run` trigger, and `workflow_run` matches a workflow by its **display name**, not its filename. Rolling that automation out across the fleet therefore needs one agreed name in every Python and JavaScript repository. The standard, now documented in the `defining-github-workflows` skill in `meta-software`, is:

- the workflow lives at `.github/workflows/ci.yml` and is named `CI`;
- it triggers on `pull_request`, and on `push` restricted to the default branch, so a feature branch does not run CI twice and the automation can rely on the pull request run;
- any `paths:` filter includes the dependency manifest and lock file, so a dependency-only pull request still runs CI;
- it never skips `dependabot[bot]`, since a skipped run means no automated review.

## What changed

- Renamed the workflow from `Continuous Integration` to `CI`.
- Limited `push` runs to `main`; pull request runs already cover feature branches.

No job, step, or matrix entry changed, so the checks that run are the same ones as before.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

Author: joshuanapoli

.github/workflows/ci.yml

@@ -1,7 +1,8 @@
-name: Continuous Integration
+name: CI
 
 on:
   push:
+    branches: [main]
     paths:
       - .github/workflows/ci.yml
       - uv.lock