refactor: wave 2 - split atlas, auto-update-checker, session-recovery, todo-enforcer, background-task hooks

- Extract atlas/ into 15 focused modules (hook, event handler, tool policies, types, etc.)
- Split auto-update-checker into checker/ and hook/ subdirectories with single-purpose files
- Decompose session-recovery into separate recovery strategy files per error type
- Extract todo-continuation-enforcer from monolith to directory with dedicated modules
- Split background-task/tools.ts into individual tool creator files
- Extract command-executor, tmux-utils into focused sub-modules
- Split config/schema.ts into domain-specific schema files
- Decompose cli/config-manager.ts into focused modules
- Rollback skill-mcp-manager, model-availability, index.ts splits that broke tests
- Fix all import path depths for moved files (../../ -> ../../../)
- Add explicit type annotations to resolve TS7006 implicit any errors

Typecheck: 0 errors
Tests: 2359 pass, 5 fail (all pre-existing)

src/hooks/todo-continuation-enforcer/handler.ts

@@ -0,0 +1,65 @@
+import type { PluginInput } from "@opencode-ai/plugin"
+
+import type { BackgroundManager } from "../../features/background-agent"
+import { log } from "../../shared/logger"
+
+import { DEFAULT_SKIP_AGENTS, HOOK_NAME } from "./constants"
+import type { SessionStateStore } from "./session-state"
+import { handleSessionIdle } from "./idle-event"
+import { handleNonIdleEvent } from "./non-idle-events"
+
+export function createTodoContinuationHandler(args: {
+  ctx: PluginInput
+  sessionStateStore: SessionStateStore
+  backgroundManager?: BackgroundManager
+  skipAgents?: string[]
+  isContinuationStopped?: (sessionID: string) => boolean
+}): (input: { event: { type: string; properties?: unknown } }) => Promise<void> {
+  const {
+    ctx,
+    sessionStateStore,
+    backgroundManager,
+    skipAgents = DEFAULT_SKIP_AGENTS,
+    isContinuationStopped,
+  } = args
+
+  return async ({ event }: { event: { type: string; properties?: unknown } }): Promise<void> => {
+    const props = event.properties as Record<string, unknown> | undefined
+
+    if (event.type === "session.error") {
+      const sessionID = props?.sessionID as string | undefined
+      if (!sessionID) return
+
+      const error = props?.error as { name?: string } | undefined
+      if (error?.name === "MessageAbortedError" || error?.name === "AbortError") {
+        const state = sessionStateStore.getState(sessionID)
+        state.abortDetectedAt = Date.now()
+        log(`[${HOOK_NAME}] Abort detected via session.error`, { sessionID, errorName: error.name })
+      }
+
+      sessionStateStore.cancelCountdown(sessionID)
+      log(`[${HOOK_NAME}] session.error`, { sessionID })
+      return
+    }
+
+    if (event.type === "session.idle") {
+      const sessionID = props?.sessionID as string | undefined
+      if (!sessionID) return
+      await handleSessionIdle({
+        ctx,
+        sessionID,
+        sessionStateStore,
+        backgroundManager,
+        skipAgents,
+        isContinuationStopped,
+      })
+      return
+    }
+
+    handleNonIdleEvent({
+      eventType: event.type,
+      properties: props,
+      sessionStateStore,
+    })
+  }
+}