feat(projman): add RFC system for feature tracking

Implement wiki-based Request for Comments system for capturing,
reviewing, and tracking feature ideas through their lifecycle.

New commands:
- /rfc-create: Create RFC from conversation or clarified spec
- /rfc-list: List RFCs grouped by status
- /rfc-review: Submit Draft RFC for review
- /rfc-approve: Approve RFC for sprint planning
- /rfc-reject: Reject RFC with documented reason

RFC lifecycle: Draft → Review → Approved → Implementing → Implemented

Integration:
- /sprint-plan detects approved RFCs and offers selection
- /sprint-close updates RFC status on completion
- clarity-assist suggests /rfc-create for feature ideas

New MCP tool: allocate_rfc_number

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

plugins/clarity-assist/commands/clarify.md

@@ -34,7 +34,31 @@ Load these skills before proceeding:
 2. **Diagnose** - Identify gaps and conflicts
 3. **Develop** - Gather clarifications via structured questions
 4. **Deliver** - Present refined specification
+5. **Offer RFC Creation** - For feature work, offer to save as RFC
 
 ## Output Format
 
 Use the Deliver phase template from `skills/4d-methodology.md` to present the clarified specification for user confirmation.
+
+## RFC Creation Offer (Step 5)
+
+After presenting the clarified specification, if the request appears to be a feature or enhancement:
+
+```
+---
+
+Would you like to save this as an RFC for formal tracking?
+
+An RFC (Request for Comments) provides:
+- Structured documentation of the proposal
+- Review workflow before implementation
+- Integration with sprint planning
+
+[1] Yes, create RFC from this specification
+[2] No, proceed with implementation directly
+```
+
+If user selects [1]:
+- Pass clarified specification to `/rfc-create`
+- The Summary, Motivation, and Design sections will be populated from the clarified spec
+- User can then refine the RFC and submit for review