Set GIT_AUTHOR_NAME per agent session (gt-6r18e.1)

Export GIT_AUTHOR_NAME alongside BD_ACTOR in all agent session startup
locations. This enables git log --author queries for agent work while
keeping GIT_AUTHOR_EMAIL as the workspace owner.

Files updated:
- internal/session/manager.go (polecat sessions)
- internal/daemon/daemon.go (deacon, witness, polecat via daemon)
- internal/daemon/lifecycle.go (polecat lifecycle)
- internal/cmd/*.go (crew, mayor, deacon, witness, refinery, up, handoff)
- internal/session/manager_test.go (updated test expectations)
- docs/federation.md (marked feature as implemented)

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

internal/session/manager.go

@@ -178,8 +178,8 @@ func (m *Manager) Start(polecat string, opts StartOptions) error {
 		// Polecats run with full permissions - Gas Town is for grownups
 		// Export env vars inline so Claude's role detection works
 		bdActor := fmt.Sprintf("%s/polecats/%s", m.rig.Name, polecat)
-		command = fmt.Sprintf("export GT_ROLE=polecat GT_RIG=%s GT_POLECAT=%s BD_ACTOR=%s && claude --dangerously-skip-permissions",
-			m.rig.Name, polecat, bdActor)
+		command = fmt.Sprintf("export GT_ROLE=polecat GT_RIG=%s GT_POLECAT=%s BD_ACTOR=%s GIT_AUTHOR_NAME=%s && claude --dangerously-skip-permissions",
+			m.rig.Name, polecat, bdActor, bdActor)
 	}
 	if err := m.tmux.SendKeys(sessionID, command); err != nil {
 		return fmt.Errorf("sending command: %w", err)