Add Slack diligence workflow starter

[pratikbuilds]

Summary

• add starter/slack-diligence, a sourced Slack diligence snapshot workflow
• parse a company and URL from a Slack mention or DM
• research public evidence, draft a structured snapshot, post the result in-thread, and upload a PDF
• reuse the shared Corbits Tag submodule introduced by PR Add Slack internal processing workflow #27

Stack

This PR is intentionally stacked on #27 (slack-internal-processing) and adds only starter/slack-diligence on top of that branch.

Verification

• bun run typecheck (from starter/slack-diligence)
• bun test (7 passing)
• git diff --check

No demo video, audio, narration, PDF renders, screenshots, or generated temporary artifacts are included.

[linear-code]

DVRL-53

[TheGreatAxios]

code-review

Adds a Slack diligence starter: Tag with Company | URL, Exa/Firecrawl research → draft workflow, Slack snapshot card, and PDF upload via filesUploadV2.

Comment

1. starter/slack-diligence/src/pdf.ts:15-149 — sync throw before document.end() leaves the returned promise unsettled

   renderDiligencePdf builds a complete promise from document.on("end"|"error"), then does sync PDFKit work and only then calls document.end(). If that sync work throws, complete never settles. session.ts treats PDF failure as soft-fail (still post the Slack card), but a hang defeats that path and leaves the thread in active forever.

   Could we wrap the sync render in try/catch and reject (or document.end() in a finally after marking failure) so await renderDiligencePdf always settles?

Notes (non-blocking)

• Thread-id parsing in slack-upload.ts matches Chat SDK slack:CHANNEL:TS (parts.pop() twice) — verified against chat-sdk docs.
• cli.ts matches slack-fact-check for subscribeOnMention: false (no registerSingleton / initialize); that is consistent for this shape.
• bun test for package tests: 7 pass. (Untracked tmp/critique-tests/ from review probing not part of the PR.)

Checks

• Single commit subject ≤72, empty body: Add Slack diligence workflow starter
• Diff scope is starter/slack-diligence/** only vs origin/slack-internal-processing

[TheGreatAxios]

code-review (re-review)

No new commits since the prior review. Prior soft-fail note still applies; one license follow-up.

Comment

1. starter/slack-diligence/src/pdf.ts — sync throw before document.end() can leave the returned promise unsettled

   Still true on tip 9efa6e0. Wrapping the sync render so complete always settles keeps the session soft-fail path (Slack card without PDF) from hanging the thread.

2. package.json declares "license": "LGPL-2.1-only"

   Please drop the per-package license field to match the repo-level MIT direction in #30.

Checks

• Diff vs origin/slack-internal-processing is still starter/slack-diligence/** only
• Thread-id parsing in slack-upload.ts still matches Chat SDK slack:CHANNEL:TS