feat: Add self-contained orchestration templates and guide

Makes Mosaic Stack self-contained for orchestration - no external dependencies.

New files:
- docs/claude/orchestrator.md - Platform-specific orchestrator protocol
- docs/templates/ - Bootstrap templates for tasks.md, learnings, reports

Templates:
- orchestrator/tasks.md.template - Task tracking scaffold
- orchestrator/orchestrator-learnings.json.template - Variance tracking
- orchestrator/orchestrator-learnings.schema.md - JSON schema docs
- orchestrator/phase-issue-body.md.template - Gitea issue body
- orchestrator/compaction-summary.md.template - 60% checkpoint format
- reports/review-report-scaffold.sh - Creates report directory
- scratchpad.md.template - Per-task working document

Updated CLAUDE.md:
- References local docs/claude/orchestrator.md instead of ~/.claude/
- Added Platform Templates section pointing to docs/templates/

This enables deployment without requiring user-level ~/.claude/ configuration.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

docs/templates/orchestrator/phase-issue-body.md.template

@@ -0,0 +1,43 @@
+## Phase ${PHASE_NUMBER}: ${PHASE_NAME}
+
+**Milestone:** ${MILESTONE}
+**Branch:** `${PHASE_BRANCH}`
+**Estimate:** ${PHASE_ESTIMATE_K}K tokens
+
+---
+
+### Scope
+
+${PHASE_SCOPE}
+
+### Tasks
+
+<!-- Generated from findings -->
+- [ ] Task 1
+- [ ] Task 2
+
+### Acceptance Criteria
+
+- [ ] All quality gates pass (lint, typecheck, tests)
+- [ ] No regressions from baseline
+- [ ] Code review approved
+- [ ] tasks.md updated with actual token usage
+
+### Dependencies
+
+**Blocked by:** ${BLOCKED_BY}
+**Blocks:** ${BLOCKS}
+
+### Quality Gates
+
+```bash
+# Run before marking tasks complete
+pnpm lint
+pnpm typecheck
+pnpm test
+```
+
+---
+
+**Tracking:** docs/tasks.md
+**Learnings:** docs/orchestrator-learnings.json