fix(startup): unify agent startup with beacon + instructions in CLI prompt (#977)

All agents now receive their startup beacon + role-specific instructions via
the CLI prompt, making sessions identifiable in /resume picker while removing
unreliable post-startup nudges.

Changes:
- Rename FormatStartupNudge → FormatStartupBeacon, StartupNudgeConfig → BeaconConfig
- Remove StartupNudge() function (no longer needed)
- Remove PropulsionNudge() and PropulsionNudgeForRole() functions
- Update deacon, witness, refinery, polecat managers to include beacon in CLI prompt
- Update boot to inline beacon (can't import session due to import cycle)
- Update daemon/lifecycle.go to include beacon via BuildCommandWithPrompt
- Update cmd/deacon.go to include beacon in startup command
- Remove redundant StartupNudge and PropulsionNudge calls from all startup paths

The beacon is now part of the CLI prompt which is queued before Claude starts,
making it more reliable than post-startup nudges which had timing issues.
SessionStart hook runs gt prime automatically, so PropulsionNudge was redundant.

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

internal/deacon/manager.go

@@ -80,10 +80,11 @@ func (m *Manager) Start(agentOverride string) error {
 		return fmt.Errorf("ensuring Claude settings: %w", err)
 	}
 
-	// Build startup command with initial prompt for autonomous patrol.
-	// The prompt triggers GUPP: deacon starts patrol immediately without waiting for input.
-	// This prevents the agent from sitting idle at the prompt after SessionStart hooks run.
-	initialPrompt := "I am Deacon. Start patrol: check gt hook, if empty create mol-deacon-patrol wisp and execute it."
+	initialPrompt := session.BuildStartupPrompt(session.BeaconConfig{
+		Recipient: "deacon",
+		Sender:    "daemon",
+		Topic:     "patrol",
+	}, "I am Deacon. Start patrol: check gt hook, if empty create mol-deacon-patrol wisp and execute it.")
 	startupCmd, err := config.BuildAgentStartupCommandWithAgentOverride("deacon", "", m.townRoot, "", initialPrompt, agentOverride)
 	if err != nil {
 		return fmt.Errorf("building startup command: %w", err)
@@ -121,19 +122,6 @@ func (m *Manager) Start(agentOverride string) error {
 
 	time.Sleep(constants.ShutdownNotifyDelay)
 
-	// Inject startup nudge for predecessor discovery via /resume
-	_ = session.StartupNudge(t, sessionID, session.StartupNudgeConfig{
-		Recipient: "deacon",
-		Sender:    "daemon",
-		Topic:     "patrol",
-	}) // Non-fatal
-
-	// GUPP: Gas Town Universal Propulsion Principle
-	// Send the propulsion nudge to trigger autonomous patrol execution.
-	// Wait for beacon to be fully processed (needs to be separate prompt)
-	time.Sleep(2 * time.Second)
-	_ = t.NudgeSession(sessionID, session.PropulsionNudgeForRole("deacon", deaconDir)) // Non-fatal
-
 	return nil
 }