Add persisted hook enablement state (#19840)

## Why

After `hooks/list` exposes the hook inventory, clients need a way to
persist user hook preferences, make those changes effective in
already-open sessions, and distinguish user-controllable hooks from
managed requirements without adding another bespoke app-server write
API.

## What

- Extends `hooks/list` entries with effective `enabled` state.
- Persists user-level hook state under `hooks.state.<hook-id>` so the
model can grow beyond a single boolean over time.
- Uses the existing `config/batchWrite` path for hook state updates
instead of introducing a dedicated hook write RPC.
- Refreshes live session hook engines after config writes so
already-open threads observe updated enablement without a restart.

## Stack

1. openai/codex#19705
2. openai/codex#19778
3. This PR - openai/codex#19840
4. openai/codex#19882

## Reviewer Notes

The generated schema files account for much of the raw diff. The core
behavior is in:

- `hooks/src/config_rules.rs`, which resolves per-hook user state from
the config layer stack.
- `hooks/src/engine/discovery.rs`, which projects effective enablement
into `hooks/list` from source-derived managedness.
- `config/src/hook_config.rs`, which defines the new `hooks.state`
representation.
- `core/src/session/mod.rs`, which rebuilds live hook state after user
config reloads.

---------

Co-authored-by: Codex <noreply@openai.com>

codex-rs/app-server-protocol/schema/json/v2/HooksListResponse.json

@@ -51,12 +51,21 @@
           "format": "int64",
           "type": "integer"
         },
+        "enabled": {
+          "type": "boolean"
+        },
         "eventName": {
           "$ref": "#/definitions/HookEventName"
         },
         "handlerType": {
           "$ref": "#/definitions/HookHandlerType"
         },
+        "isManaged": {
+          "type": "boolean"
+        },
+        "key": {
+          "type": "string"
+        },
         "matcher": {
           "type": [
             "string",
@@ -89,8 +98,11 @@
       },
       "required": [
         "displayOrder",
+        "enabled",
         "eventName",
         "handlerType",
+        "isManaged",
+        "key",
         "source",
         "sourcePath",
         "timeoutSec"
@@ -105,6 +117,7 @@
         "mdm",
         "sessionFlags",
         "plugin",
+        "cloudRequirements",
         "legacyManagedConfigFile",
         "legacyManagedConfigMdm",
         "unknown"