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/config/schema/git-master.ts

@@ -0,0 +1,10 @@
+import { z } from "zod"
+
+export const GitMasterConfigSchema = z.object({
+  /** Add "Ultraworked with Sisyphus" footer to commit messages (default: true). Can be boolean or custom string. */
+  commit_footer: z.union([z.boolean(), z.string()]).default(true),
+  /** Add "Co-authored-by: Sisyphus" trailer to commit messages (default: true) */
+  include_co_authored_by: z.boolean().default(true),
+})
+
+export type GitMasterConfig = z.infer<typeof GitMasterConfigSchema>