Complete REPO-WP-0002 template validation and bootstrap docs

Add statehub register consumer guide and validation checklist, register
capability.infotech.repo-template in the registry index, and close the
workplan after filling repo identity placeholders and README bootstrap steps.

.claude/rules/repo-identity.md

@@ -1,4 +1,4 @@
-**Purpose:** Repo Seed - (fill in purpose)
+**Purpose:** Git repository template to bootstrap coulomb projects.
 
 **Domain:** infotech
 **Repo slug:** repo-seed