Document intentional error suppressions with comments (gt-zn9m)

All 156 instances of _ = error suppression in non-test code now have
explanatory comments documenting why the error is intentionally ignored.

Categories of intentional suppressions:
- non-fatal: session works without these - tmux environment setup
- non-fatal: theming failure does not affect operation - visual styling
- best-effort cleanup - defer cleanup on failure paths
- best-effort notification - mail/notifications that should not block
- best-effort interrupt - graceful shutdown attempts
- crypto/rand.Read only fails on broken system - random ID generation
- output errors non-actionable - fmt.Fprint to io.Writer

This addresses the silent failure and debugging concerns raised in the
issue by making the intentionality explicit in the code.

Generated with Claude Code https://claude.com/claude-code

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

internal/daemon/lifecycle.go

@@ -260,13 +260,13 @@ func (d *Daemon) restartSession(sessionName, identity string) error {
 		return fmt.Errorf("creating session: %w", err)
 	}
 
-	// Set environment
+	// Set environment (non-fatal: session works without these)
 	_ = d.tmux.SetEnvironment(sessionName, "GT_ROLE", identity)
 	// BD_ACTOR uses slashes instead of dashes for path-like identity
 	bdActor := identityToBDActor(identity)
 	_ = d.tmux.SetEnvironment(sessionName, "BD_ACTOR", bdActor)
 
-	// Apply theme
+	// Apply theme (non-fatal: theming failure doesn't affect operation)
 	if identity == "mayor" {
 		theme := tmux.MayorTheme()
 		_ = d.tmux.ConfigureGasTownSession(sessionName, theme, "", "Mayor", "coordinator")