fix(crew): prevent restart when attaching to crew session with running agent (#491)

* fix(sling_test): update test for cook dir change

The cook command no longer needs database context and runs from cwd,
not the target rig directory. Update test to match this behavior
change from bd2a5ab5.

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

* fix(tests): skip tests requiring missing binaries, handle --allow-stale

- Add skipIfAgentBinaryMissing helper to skip tests when codex/gemini
  binaries aren't available in the test environment
- Update rig manager test stub to handle --allow-stale flag

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

* fix(crew): prevent restart when attaching to session with running agent

When running `gt crew at <name>` while already inside the target tmux
session, the command would unconditionally start the agent, causing
Claude to restart even if it was already running.

Add IsAgentRunning check before starting the agent when already in
the target session, matching the behavior for the external attach case.

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

---------

Co-authored-by: julianknutsen <julianknutsen@users.noreply.github>
Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>

internal/cmd/crew_at.go

@@ -262,7 +262,18 @@ func runCrewAt(cmd *cobra.Command, args []string) error {
 
 	// Check if we're already in the target session
 	if isInTmuxSession(sessionID) {
-		// We're in the session at a shell prompt - just start the agent directly
+		// Check if agent is already running - don't restart if so
+		agentCfg, _, err := config.ResolveAgentConfigWithOverride(townRoot, r.Path, crewAgentOverride)
+		if err != nil {
+			return fmt.Errorf("resolving agent: %w", err)
+		}
+		if t.IsAgentRunning(sessionID, config.ExpectedPaneCommands(agentCfg)...) {
+			// Agent is already running, nothing to do
+			fmt.Printf("Already in %s session with %s running.\n", name, agentCfg.Command)
+			return nil
+		}
+
+		// We're in the session at a shell prompt - start the agent
 		// Build startup beacon for predecessor discovery via /resume
 		address := fmt.Sprintf("%s/crew/%s", r.Name, name)
 		beacon := session.FormatStartupNudge(session.StartupNudgeConfig{
@@ -270,10 +281,6 @@ func runCrewAt(cmd *cobra.Command, args []string) error {
 			Sender:    "human",
 			Topic:     "start",
 		})
-		agentCfg, _, err := config.ResolveAgentConfigWithOverride(townRoot, r.Path, crewAgentOverride)
-		if err != nil {
-			return fmt.Errorf("resolving agent: %w", err)
-		}
 		fmt.Printf("Starting %s in current session...\n", agentCfg.Command)
 		return execAgent(agentCfg, beacon)
 	}