Slack: per-suite Run-it matching — multi-suite turns can strand a suite past the proposal cap

From the #3696 review: the legacy Run-it accessory is suppressed by a single boolean ("some run proposal will render"), not per-suite. A turn that creates 3+ suites, where a given suite's run_eval_suite proposal falls past MAX_PROPOSAL_BLOCKS=5, leaves that suite created and linked but with no way to run it from Slack.

Fix options: match proposals to suites (proposal target → suiteId) and suppress the accessory per-suite, or have the server guarantee run proposals for created suites always fit under the cap (order them first).

Files: slack-app/listeners/views/proposal-builder.js (rendersRunProposal), slack-app/listeners/events/run-and-reply.js:145.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Read slack-app/listeners/views/proposal-builder.js, especially rendersRunProposal, and slack-app/listeners/events/run-and-reply.js around line 145. Trace a turn that creates three or more suites and inspect how proposal targets, suite IDs, and MAX_PROPOSAL_BLOCKS=5 interact; done means every created suite remains runnable from Slack even when proposals reach the cap.

Written by the indexing model from the issue text.