feat: add github-native coordination (epic-* commands + scripts + tests)

Adds a GitHub-native coordination layer on top of ECC:

Commands (7 new slash commands):
- epic-claim, epic-sync, epic-validate, epic-publish
- epic-review, epic-unblock, epic-decompose

Scripts:
- scripts/github-coordination.js  — CLI entry point
- scripts/lib/github-coordination.js  — core library (state machine, gh API wrappers)
- scripts/status.js  — coordination status reporter

Config:
- config/github-native-coordination.json  — labels, review policy, validation gates

Tests:
- tests/lib/github-coordination.test.js  — 15 unit tests for pure functions
- tests/scripts/github-coordination.test.js  — integration/CLI test suite

Registry:
- docs/COMMAND-REGISTRY.json  — adds 7 epic-* entries, totalCommands 84 → 91

No encoding changes, no prp-* modifications, no Windows shims.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

commands/epic-claim.md

@@ -0,0 +1,26 @@
+---
+description: Claim an epic issue, stamp coordination state, and sync local ownership.
+---
+
+# /epic-claim
+
+Claim one epic issue as the source of truth for a unit of work.
+
+Use the coordination script:
+
+```bash
+node scripts/github-coordination.js claim <issue-number> --repo <owner/repo> --actor <login>
+```
+
+What this does:
+
+1. Loads the issue body and coordination block.
+2. Marks the epic as claimed in GitHub issue state.
+3. Updates labels and the local SQLite cache.
+4. Appends an audit comment for the claim.
+
+Compatibility aliases:
+
+- `/orch-add-feature`
+- `/orch-change-feature`
+- `/prp-implement`

commands/epic-decompose.md

@@ -0,0 +1,23 @@
+---
+description: Break an epic into task children without creating task branches.
+---
+
+# /epic-decompose
+
+Reconcile the task breakdown for one epic issue.
+
+```bash
+node scripts/github-coordination.js decompose <issue-number> --repo <owner/repo>
+```
+
+What this does:
+
+1. Reads the epic issue body for task checklists and dependency references.
+2. Stores the decomposition in the coordination block.
+3. Leaves task branches out of the workflow.
+4. Appends a concise audit comment.
+
+Compatibility aliases:
+
+- `/plan`
+- `/prp-plan`

commands/epic-publish.md

@@ -0,0 +1,23 @@
+---
+description: Publish a validated epic update back to the issue and local cache.
+---
+
+# /epic-publish
+
+Publish a validated coordination update to GitHub.
+
+```bash
+node scripts/github-coordination.js publish <issue-number> --repo <owner/repo>
+```
+
+What this does:
+
+1. Re-validates the epic before publishing.
+2. Updates the coordination block in the issue body.
+3. Appends a concise publish comment.
+4. Records the final local snapshot.
+
+Compatibility aliases:
+
+- `/pr`
+- `/prp-pr`

commands/epic-review.md

@@ -0,0 +1,23 @@
+---
+description: Mark epic review requested, approved, or changes requested.
+---
+
+# /epic-review
+
+Coordinate review state for an epic issue.
+
+```bash
+node scripts/github-coordination.js review <issue-number> --repo <owner/repo> --review approved
+```
+
+What this does:
+
+1. Updates the review state in the coordination block.
+2. Syncs review labels to GitHub.
+3. Records the review outcome in an audit comment.
+4. Keeps the local cache aligned with the issue body.
+
+Compatibility aliases:
+
+- `/review-pr`
+- `/code-review`

commands/epic-sync.md

@@ -0,0 +1,23 @@
+---
+description: Sync epic issue bodies, labels, and local coordination snapshots from GitHub.
+---
+
+# /epic-sync
+
+Run a deterministic sync for epic issues.
+
+```bash
+node scripts/github-coordination.js sync --repo <owner/repo>
+```
+
+What this does:
+
+1. Reads issue bodies as the canonical epic state.
+2. Reconciles the coordination block with labels.
+3. Writes a fresh local snapshot for each epic issue.
+4. Keeps the SQLite cache aligned with GitHub.
+
+Compatibility aliases:
+
+- `/projects`
+- `/work-items sync-github`

commands/epic-unblock.md

@@ -0,0 +1,22 @@
+---
+description: Sweep blocked epic issues and reopen anything whose dependencies are closed.
+---
+
+# /epic-unblock
+
+Sweep blocked epics whose declared dependencies are complete.
+
+```bash
+node scripts/github-coordination.js unblock --repo <owner/repo>
+```
+
+What this does:
+
+1. Scans epic issues in the repository.
+2. Checks each blocked epic's dependency list.
+3. Moves fully unblocked epics to ready.
+4. Updates labels, comments, and local snapshots.
+
+Compatibility aliases:
+
+- `/loop-status`

commands/epic-validate.md

@@ -0,0 +1,22 @@
+---
+description: Validate epic readiness, dependencies, and coordination policy.
+---
+
+# /epic-validate
+
+Validate a single epic issue before publishing or review handoff.
+
+```bash
+node scripts/github-coordination.js validate <issue-number> --repo <owner/repo>
+```
+
+What this checks:
+
+1. Coordination state exists and is parseable.
+2. Validation state is satisfied by policy.
+3. Declared dependencies are closed.
+4. The epic is ready for the next workflow stage.
+
+Compatibility aliases:
+
+- `/quality-gate`