CIP-0002: mark material review as in progress

Update CIP-0002 status to In Progress and record the start of implementation.

Author: lawrennd

cip/cip0002.md

@@ -2,8 +2,8 @@
 author: "Neil D. Lawrence"
 created: "2026-01-27"
 id: "0002"
-last_updated: "2026-01-27"
-status: "Proposed"
+last_updated: "2026-01-28"
+status: "In Progress"
 compressed: false
 related_requirements:
   - "0001"
@@ -25,8 +25,8 @@ title: "Material review: chapters, talks, and snippet freshness"
 ## Status
 
 - [x] Proposed - Initial idea documented
-- [ ] Accepted - Approved, ready to start work
-- [ ] In Progress - Actively being implemented
+- [x] Accepted - Approved, ready to start work
+- [x] In Progress - Actively being implemented
 - [ ] Implemented - Work complete, awaiting verification
 - [ ] Closed - Verified and complete
 - [ ] Rejected