[Merged by Bors] - feat(ci): add CI status emoji reactions to Zulip messages

[kim-em]

This PR extends the emojibot to show CI build status on Zulip messages that mention a PR:

• 🟡 CI running
• ✅ CI passed
• ❌ CI failed

These are independent of the existing PR status emojis (merged, delegated, awaiting-author, etc.) and can coexist with them.

The new zulip_emoji_ci_status.yaml workflow triggers on workflow_run events from both CI workflows. Cancelled runs are ignored (a new run will follow shortly).

🤖 Prepared with Claude Code

[github-actions]

PR summary d037817051

Import changes for modified files

No significant changes to the import graph

Import changes for all files

Files	Import difference

---

Declarations diff

No declarations were harmed in the making of this PR! 🐙

You can run this locally as follows

## summary with just the declaration names:
./scripts/declarations_diff.sh <optional_commit>

## more verbose report:
./scripts/declarations_diff.sh long <optional_commit>

The doc-module for script/declarations_diff.sh contains some details about this script.

---

No changes to technical debt.

You can run this locally as

./scripts/technical-debt-metrics.sh pr_summary

• The relative value is the weighted sum of the differences with weight given by the inverse of the current value of the statistic.
• The absolute value is the relative value divided by the total sum of the inverses of the current values (i.e. the weighted average of the differences).

[bryangingechen]

Let's try it out!
Thanks!
bors r+

[mathlib-bors]

Pull request successfully merged into master.

Build succeeded:

• ci (staging) / Lint style
• ci (staging) / Post-CI job
• ci (staging) / Build
• ci (staging) / Post-Build Step