wiki(claude): add session-handoff trigger line

Pulls in `session handoff: read on start, write on end` so the
session-handoff skill (installed via claude-skills) activates in this
project. Inserted between `pull remote before work` and
`follow project discipline` — session-lifecycle clustering, mirrors
claude-skills CLAUDE.md and project-bootstrap's canonical template.

Refs OpeItcLoc03/claude-skills [session-handoff-existing-projects-upgrade].

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

CLAUDE.md

@@ -7,6 +7,7 @@ use project wiki
 use task management system
 check across all projects
 pull remote before work
+session handoff: read on start, write on end
 follow project discipline
 delegate to interns when allowed
 recommend, don't menu