[docs] Introduce required/optional OB1 compatibility contract

[justfinethanku]

Summary

• Breaking schema change. requires.open_brain migrates from the boolean const true to a string enum: "required" | "optional".
• Bulk-migrates every existing metadata.json (66 files total) to the new shape and reclassifies the nine standalone skill packs as "optional".
• Rewrites skills/README.md with a new Works without OB1? column and a compatibility legend. Adds a one-paragraph note under the skills section of the root README.md.

Why this change

The old contract forced every contribution to declare open_brain: true, which overstated the dependency. Many skills in skills/ (competitive-analysis, deal-memo-drafting, financial-model-review, meeting-synthesis, research-synthesis, heavy-file-ingestion, n-agentic-harnesses, panning-for-gold, claudeception) are genuinely useful on their own — Open Brain hooks are additive, not required.

The new contract lets the upcoming community catalog (PR2) and the public /ob1 directory on natejones.com (separate repo) surface that distinction accurately instead of overselling the dependency.

Classification decisions in this PR

• All recipes, primitives, extensions, schemas, dashboards, and integrations → "required". Nothing in those categories works without the core OB1 stack in v1.
• Skills declared "required" (4): auto-capture, autodream-brain-sync, weekly-signal-diff, work-operating-model — each explicitly calls OB1 MCP tools or depends on OB1 data shapes.
• Skills declared "optional" (9): claudeception, competitive-analysis, deal-memo-drafting, financial-model-review, heavy-file-ingestion, meeting-synthesis, n-agentic-harnesses, panning-for-gold, research-synthesis.

Files changed

• .github/metadata.schema.json — enum swap, description updated
• CONTRIBUTING.md — documents the new contract + both values
• extensions/_template/AGENT_SPEC.md — template sample updated
• README.md — short note under /skills explaining the split
• skills/README.md — new column, legend, and contributing guidance
• 66 × metadata.json — bulk migration to "required" or "optional"

Follow-up PR

PR2 ships the catalog generator script plus the committed resources/ob1-catalog.json artifact and a gate drift check. PR2 depends on this contract landing first.

In-flight contribution branches

Any open PR whose metadata.json still sets open_brain: true will fail the Metadata valid check after this merges. Maintainer-side fix on merge is the expected remediation (contributor volume is low). We should post a short note on the repo discussion / Discord once this lands so active contributors can rebase.

Test plan

• check-jsonschema --schemafile .github/metadata.schema.json <every metadata.json> passes locally (all 66 files)
• Gate workflow skips contribution checks for [docs]-tagged PRs (line 75 in ob1-gate.yml)
• Post-merge: verify catalog generator in PR2 ingests every contribution cleanly
• Post-merge: check that any currently open contribution PR gets a clear failure message pointing at this migration

🤖 Generated with Claude Code

[alanshurafa]

The required/optional compatibility-contract idea reads well. The blocker is scope: this change spans 71 files, including a breaking metadata.schema.json enum change that would fail the gate on every open contribution PR until each one is rebased.

Recommend author refresh, and worth considering a split — the schema plus CONTRIBUTING.md update, the bulk metadata.json migration, and the skills README could each land as a separate, smaller PR. That would make each piece easier to review and easier to coordinate with the in-flight contribution PRs. Flagged for the maintainer, since rolling out a breaking contract change is a sequencing decision.

— Alan (community reviewer; non-binding)