fix: auto-continuation silently dropped LLM errors + added outer retry

Verified live: the new auto-continuation worker (previous commit) worked end
to end for the happy path (provision -> auto-verify -> report success, zero
operator ticks). But testing a failure-recovery case (a destroy that failed
because the container was still running) surfaced a real bug: continueSession's
emit closure only captured "text" events, so when chatWith ended the turn on
an "error" event (LLM returned an empty/refusal response, internal retry also
empty), the worker persisted a completely blank, uninformative "auto" message
— no sign anything had gone wrong, undermining observability of the very
mechanism just built.

- Capture "error" events and, if the turn produced no text/tool_calls at all,
  persist an explanatory placeholder instead of blank.
- Add one outer retry of the whole chatWith call when the first attempt
  produces nothing — the principle behind this whole feature ("don't give up
  on the first error") should apply to the continuation mechanism itself, not
  just the homelab commands it's continuing.

Also verified live: recovery-from-failure works via the normal chat path once
prompted, and cleaned up the test container.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

cmd/nomos/continue.go

@@ -80,27 +80,50 @@ func (a *agent) continueSession(ctx context.Context, p pendingContinuation) {
 	slog.Info("nomos: auto-continuing session", "session", p.SessionID, "execution", p.ExecID, "status", p.Status)
 
 	var toolCalls []map[string]any
-	var finalText string
-	emit := func(ev agentEvent) {
-		if ev.Type == "tool_use" || ev.Type == "tool_result" {
-			if m, ok := ev.Data.(map[string]any); ok {
-				m["type"] = ev.Type
-				toolCalls = append(toolCalls, m)
+	var finalText, errText string
+
+	// One retry if the LLM call itself produced nothing (transient flake /
+	// empty-response) — the whole point of this mechanism is "don't give up
+	// on the first error," which should apply to the continuation call
+	// itself, not just the homelab commands it's continuing. Found live: a
+	// destructive-recovery continuation hit an empty LLM response, its
+	// internal retry (chatWith's own maxLLMRetries=1) also came up empty, and
+	// without this outer retry the operator would see nothing at all.
+	cctx, cancel := context.WithTimeout(ctx, 10*time.Minute)
+	defer cancel()
+	for attempt := 0; attempt < 2; attempt++ {
+		toolCalls, finalText, errText = nil, "", ""
+		emit := func(ev agentEvent) {
+			if ev.Type == "tool_use" || ev.Type == "tool_result" {
+				if m, ok := ev.Data.(map[string]any); ok {
+					m["type"] = ev.Type
+					toolCalls = append(toolCalls, m)
+				}
+			}
+			if ev.Type == "text" {
+				finalText, _ = ev.Data.(string)
+			}
+			if ev.Type == "error" {
+				errText, _ = ev.Data.(string)
 			}
 		}
-		if ev.Type == "text" {
-			finalText, _ = ev.Data.(string)
+		a.chatWith(cctx, p.SessionID, "", note, emit)
+		if finalText != "" || len(toolCalls) > 0 {
+			break
+		}
+		if attempt == 0 {
+			slog.Warn("nomos: auto-continuation produced nothing, retrying once", "session", p.SessionID, "execution", p.ExecID, "error", errText)
 		}
 	}
 
-	// Use a generous timeout: a continuation may itself launch further steps.
-	cctx, cancel := context.WithTimeout(ctx, 10*time.Minute)
-	defer cancel()
-	a.chatWith(cctx, p.SessionID, "", note, emit)
-
+	text := finalText
+	if text == "" && errText != "" {
+		text = fmt.Sprintf("(auto-continuation hit an internal error and did not respond: %s — the execution's own result is above; you may need to prompt the agent again)", errText)
+		slog.Error("nomos: auto-continuation produced no response after retry", "session", p.SessionID, "execution", p.ExecID, "error", errText)
+	}
 	assistantMsg, _ := json.Marshal(map[string]any{
 		"role":       "assistant",
-		"text":       finalText,
+		"text":       text,
 		"tool_calls": toolCalls,
 		"auto":       true, // marks this as an autonomous continuation, not an operator turn
 	})