Change feed hotkey from C-b f to C-b a (activity)

C-b f conflicts with tmux built-in find-window command.

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

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

internal/tmux/tmux.go

@@ -674,13 +674,13 @@ func (t *Tmux) SetCrewCycleBindings(session string) error {
 	return nil
 }
 
-// SetFeedBinding configures C-b f to jump to the activity feed window.
+// SetFeedBinding configures C-b a to jump to the activity feed window.
 // This creates the feed window if it doesn't exist, or switches to it if it does.
 // Uses `gt feed --window` which handles both creation and switching.
 func (t *Tmux) SetFeedBinding(session string) error {
-	// C-b f → gt feed --window (jump to feed window, creating if needed)
+	// C-b a → gt feed --window (jump to activity feed window, creating if needed)
 	// The feed command detects the current session from tmux environment
-	_, err := t.run("bind-key", "-T", "prefix", "f",
+	_, err := t.run("bind-key", "-T", "prefix", "a",
 		"run-shell", "gt feed --window")
 	return err
 }