fix: include original file name in compact message output

[jprichardson]

Summary

• CompactSlackMessage.files only included mimetype, mode, and path — the human-readable filename from Slack was dropped during compaction
• Files were saved and referenced by Slack file ID (e.g. F08ABCD1234.pdf) instead of the original name (e.g. Q4 Report.pdf)
• Added name field to the compact file output, sourced from SlackFileSummary.name

Before:

{ "mimetype": "application/pdf", "mode": "hosted", "path": "/tmp/downloads/F08ABCD1234.pdf" }

After:

{ "name": "Q4 Report.pdf", "mimetype": "application/pdf", "mode": "hosted", "path": "/tmp/downloads/F08ABCD1234.pdf" }

Changes

• name maps to f.name only (not f.title) — keeps the field narrowly defined as the actual filename
• Added test/message-compact.test.ts with 3 test cases for serialized output
• Documented file fields in skills/agent-slack/references/output.md

Test plan

• bun test — 129 tests pass (includes new message-compact tests)
• bun run lint — clean
• bun run format:check — clean
• Verified with bun run dev -- message get <url> that name field appears with the original Slack filename

🤖 Generated with Claude Code

[AmethystLiang]

This is a nice improvement. Adding a human-meaningful file label next to files[].path will make the output much easier for agents to use.

One small request before merging: could we make files[].name map to f.name only, instead of f.name || f.title? f.name is usually the actual filename, while title is more of a display label in Slack, so keeping name narrowly defined will make the JSON more predictable for downstream agents.

Could you also add a small test for the serialized output and update the README / skill docs to mention the new field? Since this changes the public JSON shape, it would be good to land the behavior, tests, and docs together.

If you make those changes, I’m happy to land this.

[jprichardson]

Thanks for the review! Addressed all three points:

1. name narrowed — now maps to f.name only (not f.name || f.title)
2. Test added — test/message-compact.test.ts with 3 cases: name present, name missing (no title fallback), and files without download paths
3. Docs updated — added "File fields in compact messages" section to skills/agent-slack/references/output.md

Also rebased onto current main (v0.6.0).

[AmethystLiang]

Reviewed the follow-up. README and skill docs now match the new files[].name output, and the new test helper typechecks.