chore: add primitive stack graph workflow

[macbotmini-eng]

Summary

Adds a GitHub-native primitive stack graph reporter for #558.

This keeps the #471 and #473 dependency picture current without requiring a database, server, or external runtime. GitHub Actions runs the reporter, reads live issue/PR state, and upserts one managed report comment on #558.

What this adds

• scripts/primitive-stack-graph.ts
  • report: prints the current Markdown/Mermaid graph
  • check: checks graph drift and exits nonzero only for critical drift
  • sync: creates or edits the managed ✍️ Primitive evaluation: #471 and #473 build path #558 graph comment marked with <!-- primitive-stack-graph-report -->
• .github/workflows/primitive-stack-graph.yml
  • manual dispatch
  • six-hour schedule
  • issue event trigger
  • pull request target trigger

Scope

This does not edit the #558 issue body. The #558 body remains the protected starting snapshot. Current state is maintained through a managed comment.

This is repo automation, not a BFF skill and not a DeFi primitive.

Current graph coverage

The reporter tracks:

• ✍️ Primitive evaluation: #471 and #473 build path #558 as the primitive evaluation index / timeline
• Skill Idea #2: HODLMM-Zest Yield Maximizer (DCA + HODLMM + Zest) #471 and 🧭 PRD: META Skill Idea #4: Leveraged sBTC via Zest + Bitflow #473 as the two loop goals
• 📑 PRD: bitflow-hodlmm-withdraw HODLMM withdrawal primitive #550/📑 PR: bitflow-hodlmm-withdraw-primitive #551, 📑 PRD: bitflow-hodlmm-deposit HODLMM deposit primitive #553/📑 PR: bitflow-hodlmm-deposit-primitive #556, and 📑 PRD: Bitflow HODLMM-Zest yield loop #559 for the Skill Idea #2: HODLMM-Zest Yield Maximizer (DCA + HODLMM + Zest) #471 HODLMM-Zest path
• 📝 PRD: zest-borrow-asset-primitive #566/📑 PR: feat(zest-borrow-asset-primitive): add Zest V2 borrow primitive #572, 📑 PRD: zest-asset-deposit-primitive #573/📑PR: feat(zest-asset-deposit-primitive): add Zest V2 deposit primitive #574, 📑 PRD: bitflow-swap-aggregator #576/📑 PR: feat(bitflow-swap-aggregator): add Bitflow aggregator swap primitive #577, 📑 PRD: Bitflow + Zest sBTC leverage cycle #561/📑 feat(bitflow-zest-sbtc-leverage-cycle): compose primitive leverage cycle #578, and 📑 PRD: sbtc-leverage-unwind-planner #562 for the 🧭 PRD: META Skill Idea #4: Leveraged sBTC via Zest + Bitflow #473 leverage path
• 📑 PRD: zest-borrow-asset primitive #560, 📑 PRD-zest-borrow-asset-agnostic-primitive #570, feat(bitflow-zest-sbtc-leverage-cycle): add Bitflow + Zest sBTC leverage cycle with resume safety #575, and [AIBTC Skills Comp Day 20] sbtc-leverage-looper — first leveraged sBTC long on Stacks via Zest + Bitflow HODLMM #348 as superseded or historical context
• feat(sbtc-yield-maximizer): complete HODLMM routing leg aibtcdev/skills#340 as the external upstream Skill Idea #2: HODLMM-Zest Yield Maximizer (DCA + HODLMM + Zest) #471 HODLMM continuation

Validation

• bun run scripts/primitive-stack-graph.ts check passed
• bun run scripts/primitive-stack-graph.ts report generated the current graph
• workflow YAML parse passed
• git diff --check passed
• public report leak scan passed

Current non-failing follow-ups from the graph check:

• 📑 feat(bitflow-zest-sbtc-leverage-cycle): compose primitive leverage cycle #578 is still draft
• feat(sbtc-yield-maximizer): complete HODLMM routing leg aibtcdev/skills#340 remains changes-requested
• 📑 PRD: sbtc-leverage-unwind-planner #562 has no implementation PR yet

[macbotmini-eng]

Updated the graph reporter in 298140d to make the generated #558 report easier to read for humans.

Changes:

• Added the 🍔 marker to MacBotMini implementation PR nodes in the Mermaid graph and the core-stack table.
• Reworded the ✍️ Primitive evaluation: #471 and #473 build path #558 timeline entry for the 🧭 PRD: META Skill Idea #4: Leveraged sBTC via Zest + Bitflow #473 correction so it uses full names: Leveraged sBTC via Zest + Bitflow (#473), #566 zest-borrow-asset-primitive PRD, and #572 zest-borrow-asset-primitive implementation PR.
• Left the protected ✍️ Primitive evaluation: #471 and #473 build path #558 issue body untouched; this still only manages the generated report comment.

Validation:

• git diff --check origin/main...HEAD passed.
• bun run scripts/primitive-stack-graph.ts check passed with authenticated GitHub reads.
• bun run scripts/primitive-stack-graph.ts report generated the updated Mermaid/table output.
• GitHub validate is passing on head 298140d.