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/constants.ts

@@ -0,0 +1,19 @@
+import { createSystemDirective, SystemDirectiveTypes } from "../../shared/system-directive"
+
+export const HOOK_NAME = "todo-continuation-enforcer"
+
+export const DEFAULT_SKIP_AGENTS = ["prometheus", "compaction"]
+
+export const CONTINUATION_PROMPT = `${createSystemDirective(SystemDirectiveTypes.TODO_CONTINUATION)}
+
+Incomplete tasks remain in your todo list. Continue working on the next pending task.
+
+- Proceed without asking for permission
+- Mark each task complete when finished
+- Do not stop until all tasks are done`
+
+export const COUNTDOWN_SECONDS = 2
+export const TOAST_DURATION_MS = 900
+export const COUNTDOWN_GRACE_PERIOD_MS = 500
+
+export const ABORT_WINDOW_MS = 3000