fix: shore up pr and job monitoring

[todpunk]

This should give us:

• A single rolling comment per (PR, commit) summarizing all checks for that commit. New commits naturally get a new comment (good history).
• Each job registers as a pending GitHub check the moment it's submitted, regardless of whether it came from eval, an API submission, or another trigger. This lets "require all checks pass" branch protection Just Work.
• After merge, the rolling-comment flow stops. New post-merge job results get their own comments, starting as "submitted" and updating through their lifecycle.
• Webapp updates jobs and logs live via WebSockets (vanilla JS, no framework).
• URLs and duration formatting are correct.

[catalystcommunityci]

Reactorcide checks — e4bdc1c

Job	Status	Duration	Link
eval: PR #57 opened on catalystcommunity/reactorcide	✅ succeeded	39.285s	details
conventional-commits	✅ succeeded	14.378s	details
test-go	✅ succeeded	427.943s	details
test-python	✅ succeeded	113.280s	details
test-web	✅ succeeded	219.136s	details

_{Updated 2026-04-22T05:51:03Z ·}

[catalystcommunityci]

Reactorcide checks — 179ed93

Job	Status	Duration	Link
eval: PR #57 updated on catalystcommunity/reactorcide	✅ succeeded	49.891s	details
conventional-commits	✅ succeeded	17.462s	details
test-go	✅ succeeded	613.093s	details
test-python	✅ succeeded	84.104s	details
test-web	✅ succeeded	399.473s	details

_{Updated 2026-04-23T02:04:01Z ·}