merge: integrate origin/dev into modular-enforcement branch

Resolves all merge conflicts, preserving our split module structure
while integrating all dev changes:
- Custom agent summaries support (parseRegisteredAgentSummaries)
- Background notification queue (enqueueNotificationForParent)
- Atlas shared git-worktree module (collectGitDiffStats, formatFileChanges)
- Ralph-loop withTimeout + DEFAULT_API_TIMEOUT=5000
- Session recovery assistant_prefill_unsupported error type
- Atlas agentOverrides forwarding
- Config handler plan model demotion (buildPlanDemoteConfig)
- Delegate-task agentOverrides, promptSyncWithModelSuggestionRetry, variant
- LSP init timeout + stale init detection
- isPlanFamily function + task-continuation-enforcer hook
- Handoff command

src/agents/custom-agent-summaries.ts

@@ -0,0 +1,61 @@
+import type { AgentPromptMetadata } from "./types"
+import { truncateDescription } from "../shared/truncate-description"
+
+type RegisteredAgentSummary = {
+  name: string
+  description: string
+}
+
+function sanitizeMarkdownTableCell(value: string): string {
+  return value
+    .replace(/\r?\n/g, " ")
+    .replace(/\|/g, "\\|")
+    .replace(/\s+/g, " ")
+    .trim()
+}
+
+function isRecord(value: unknown): value is Record<string, unknown> {
+  return typeof value === "object" && value !== null
+}
+
+export function parseRegisteredAgentSummaries(input: unknown): RegisteredAgentSummary[] {
+  if (!Array.isArray(input)) return []
+
+  const result: RegisteredAgentSummary[] = []
+  for (const item of input) {
+    if (!isRecord(item)) continue
+
+    const name = typeof item.name === "string" ? item.name : undefined
+    if (!name) continue
+
+    const hidden = item.hidden
+    if (hidden === true) continue
+
+    const disabled = item.disabled
+    if (disabled === true) continue
+
+    const enabled = item.enabled
+    if (enabled === false) continue
+
+    const description = typeof item.description === "string" ? item.description : ""
+    result.push({ name, description: sanitizeMarkdownTableCell(description) })
+  }
+
+  return result
+}
+
+export function buildCustomAgentMetadata(agentName: string, description: string): AgentPromptMetadata {
+  const shortDescription = sanitizeMarkdownTableCell(truncateDescription(description))
+  const safeAgentName = sanitizeMarkdownTableCell(agentName)
+
+  return {
+    category: "specialist",
+    cost: "CHEAP",
+    triggers: [
+      {
+        domain: `Custom agent: ${safeAgentName}`,
+        trigger: shortDescription || "Use when this agent's description matches the task",
+      },
+    ],
+  }
+}