docs(ISSUE-WP-0006): Forgejo-only language and projection boundary

Prefer Forgejo as the self-hosted forge product. Keep Gitea only as the
Gitea-compatible API identifier (module backends/gitea, type string
gitea). FORGEJO_TOKEN is preferred; GITEA_* remains a deprecated alias.

INTENT/SCOPE quote ACT-ADR-005: issue-core is not the fleet ops claim
queue. Connector docs describe repo work record → hub index → optional
Forgejo projection, not activity-core → issue-core → harness.

Assistant: grok
Assistant-Session: 01a09dc6-3f0d-7c93-8b11-8e83c0623d49

registry/indexes/capabilities.yaml

@@ -4,7 +4,7 @@ domain: helix_forge
 capabilities:
 - id: capability.infotech.issue-tracking
   name: Universal Issue Tracking Coordination
-  summary: Unified Python/CLI interface for issue tracking across Gitea, GitHub, and GitLab, preventing
+  summary: Unified Python/CLI interface for issue tracking across Forgejo, GitHub, and GitLab, preventing
     direct platform API usage and credential sprawl for coordinating agents.
   vector: D4 / A2 / C2 / R1
   domain: infotech