Support MCP tools in hooks (#18385)

## Summary

Lifecycle hooks currently treat `PreToolUse`, `PostToolUse`, and
`PermissionRequest` as Bash-only flows
- hook schema constrains `tool_name` to `Bash`
- hook input assumes a command-shaped `tool_input`
- core hook dispatch path passes only shell command strings

That means hooks cannot target MCP tools even though MCP tool names are
model-visible and stable

This change generalizes those hook paths so they can match and receive
payloads for MCP tools while preserving the existing Bash behavior.

## Reviewer Notes

I think these are the key files
- `codex-rs/core/src/tools/handlers/mcp.rs`
- `codex-rs/core/src/mcp_tool_call.rs`

Otherwise the changes across apply_patch, shell, and unified_exec are
mainly to rewire everything to be `tool_input` based instead of just
`command` so that it'll make sense for MCP tools.

## Changes

- Allow `PreToolUse`, `PostToolUse`, and `PermissionRequest` hook inputs
to carry arbitrary `tool_name` and `tool_input` values instead of
hard-coding `Bash` and command-only payloads.
- Add MCP hook payload support through `McpHandler`, using the
model-visible tool name from `ToolInvocation` and the raw MCP arguments
as `tool_input`.
- Include MCP tool responses in `PostToolUse` by serializing
`McpToolOutput` into the hook response payload.
- Run `PermissionRequest` hooks for MCP approval requests after
remembered approval checks and before falling back to user-facing MCP
elicitation.
- Preserve exact matching for literal hook matchers like `Bash` and
`mcp__memory__create_entities`, while keeping regex matcher support for
patterns like `mcp__memory__.*` and `mcp__.*__write.*`.

---------

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

codex-rs/hooks/schema/generated/permission-request.command.input.schema.json

@@ -7,21 +7,6 @@
         "string",
         "null"
       ]
-    },
-    "PermissionRequestToolInput": {
-      "additionalProperties": false,
-      "properties": {
-        "command": {
-          "type": "string"
-        },
-        "description": {
-          "type": "string"
-        }
-      },
-      "required": [
-        "command"
-      ],
-      "type": "object"
     }
   },
   "properties": {
@@ -48,9 +33,7 @@
     "session_id": {
       "type": "string"
     },
-    "tool_input": {
-      "$ref": "#/definitions/PermissionRequestToolInput"
-    },
+    "tool_input": true,
     "tool_name": {
       "type": "string"
     },