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/core/config.schema.json

@@ -884,53 +884,6 @@
         }
       ]
     },
-    "HookEventsToml": {
-      "properties": {
-        "PermissionRequest": {
-          "default": [],
-          "items": {
-            "$ref": "#/definitions/MatcherGroup"
-          },
-          "type": "array"
-        },
-        "PostToolUse": {
-          "default": [],
-          "items": {
-            "$ref": "#/definitions/MatcherGroup"
-          },
-          "type": "array"
-        },
-        "PreToolUse": {
-          "default": [],
-          "items": {
-            "$ref": "#/definitions/MatcherGroup"
-          },
-          "type": "array"
-        },
-        "SessionStart": {
-          "default": [],
-          "items": {
-            "$ref": "#/definitions/MatcherGroup"
-          },
-          "type": "array"
-        },
-        "Stop": {
-          "default": [],
-          "items": {
-            "$ref": "#/definitions/MatcherGroup"
-          },
-          "type": "array"
-        },
-        "UserPromptSubmit": {
-          "default": [],
-          "items": {
-            "$ref": "#/definitions/MatcherGroup"
-          },
-          "type": "array"
-        }
-      },
-      "type": "object"
-    },
     "HookHandlerConfig": {
       "oneOf": [
         {
@@ -995,6 +948,67 @@
         }
       ]
     },
+    "HookStateToml": {
+      "properties": {
+        "enabled": {
+          "type": "boolean"
+        }
+      },
+      "type": "object"
+    },
+    "HooksToml": {
+      "properties": {
+        "PermissionRequest": {
+          "default": [],
+          "items": {
+            "$ref": "#/definitions/MatcherGroup"
+          },
+          "type": "array"
+        },
+        "PostToolUse": {
+          "default": [],
+          "items": {
+            "$ref": "#/definitions/MatcherGroup"
+          },
+          "type": "array"
+        },
+        "PreToolUse": {
+          "default": [],
+          "items": {
+            "$ref": "#/definitions/MatcherGroup"
+          },
+          "type": "array"
+        },
+        "SessionStart": {
+          "default": [],
+          "items": {
+            "$ref": "#/definitions/MatcherGroup"
+          },
+          "type": "array"
+        },
+        "Stop": {
+          "default": [],
+          "items": {
+            "$ref": "#/definitions/MatcherGroup"
+          },
+          "type": "array"
+        },
+        "UserPromptSubmit": {
+          "default": [],
+          "items": {
+            "$ref": "#/definitions/MatcherGroup"
+          },
+          "type": "array"
+        },
+        "state": {
+          "additionalProperties": {
+            "$ref": "#/definitions/HookStateToml"
+          },
+          "type": "object"
+        }
+      },
+      "type": "object"
+    },
     "KeybindingsSpec": {
       "anyOf": [
         {
@@ -3653,10 +3667,10 @@
     "hooks": {
       "allOf": [
         {
-          "$ref": "#/definitions/HookEventsToml"
+          "$ref": "#/definitions/HooksToml"
         }
       ],
-      "description": "Lifecycle hooks configured inline in TOML."
+      "description": "Lifecycle hooks configured inline in TOML plus user-level overrides."
     },
     "include_apps_instructions": {
       "description": "Whether to inject the `<apps_instructions>` developer block.",