refactor(modules): re-tier approvals as default; extract self-mod as optional

Promotes approvals to the default tier with a public API (requestApproval +
registerApprovalHandler) that other modules consume. Self-modification
(install_packages / request_rebuild / add_mcp_server) moves into a new
optional module that registers delivery actions + matching approval handlers
via the new API.

## Approvals (default tier)

- Adds `src/modules/approvals/primitive.ts` exporting `requestApproval`,
  `registerApprovalHandler`, `notifyAgent`. Absorbs `pickApprover` /
  `pickApprovalDelivery` / `channelTypeOf` from the deleted `src/access.ts`.
- Rewrites `response-handler.ts` to dispatch to registered approval handlers
  on approve (action-keyed Map). Reject path is centralized.
- Drops the three self-mod-specific delivery-action registrations from
  `approvals/index.ts`; they belong to self-mod now.
- `onecli-approvals.ts` now imports picks from the primitive instead of
  `src/access.ts`.

## Self-mod (optional tier)

- New `src/modules/self-mod/` with request handlers (validate input + call
  requestApproval) and apply handlers (orchestration on approve).
- `apply.ts` owns updateContainerConfig + buildAgentGroupImage + killContainer
  calls. Self-mod depends on approvals (via registerApprovalHandler +
  requestApproval + notifyAgent) and on core (container-runner, container-config).
- Registers 3 delivery actions + 3 approval handlers at import time.

## Other changes

- `src/access.ts` and `src/access.test.ts` deleted. Tests split across
  `src/modules/approvals/picks.test.ts` (approver selection) and
  `src/modules/permissions/permissions.test.ts` (access + roles + DM).
- `src/modules/index.ts` barrel: approvals loads before self-mod so
  registerApprovalHandler is bound when self-mod registers at import time.

## Validation

- `pnpm run build` clean
- `pnpm test` — 137 host tests pass
- `bun test` in container/agent-runner — 17 tests pass
- Service starts; boot log shows `OneCLI approval handler started`,
  `NanoClaw running`; clean SIGTERM shutdown

Resolves the transitional tier violation flagged in PR #5 where core
imported from the permissions optional module via `src/access.ts`.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/modules/index.ts

@@ -13,9 +13,13 @@
  * Registry-based modules (installed via /add-<name> skills, pulled from the
  * `modules` branch): append imports below.
  */
-import './interactive/index.js';
+// Approvals (default tier) must load before self-mod (optional) so the
+// registerApprovalHandler / requestApproval symbols are bound when self-mod
+// registers its handlers at import time.
 import './approvals/index.js';
+import './interactive/index.js';
 import './scheduling/index.js';
 import './permissions/index.js';
 import './agent-to-agent/index.js';
+import './self-mod/index.js';