Fix README: Codex does have PreToolUse hook support (#299)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

README.md

@@ -75,7 +75,7 @@ pip install graphifyy && graphify install
 | Cursor | `graphify cursor install` |
 | Google Antigravity | `graphify antigravity install` |
 
-Codex users also need `multi_agent = true` under `[features]` in `~/.codex/config.toml` for parallel extraction. Factory Droid uses the `Task` tool for parallel subagent dispatch. OpenClaw and Aider use sequential extraction (parallel agent support is still early on those platforms). Trae uses the Agent tool for parallel subagent dispatch and does **not** support PreToolUse hooks — AGENTS.md is the always-on mechanism.
+Codex users also need `multi_agent = true` under `[features]` in `~/.codex/config.toml` for parallel extraction. Factory Droid uses the `Task` tool for parallel subagent dispatch. OpenClaw and Aider use sequential extraction (parallel agent support is still early on those platforms). Trae uses the Agent tool for parallel subagent dispatch and does **not** support PreToolUse hooks — AGENTS.md is the always-on mechanism. Codex supports PreToolUse hooks — `graphify codex install` installs one in `.codex/hooks.json` in addition to writing AGENTS.md.
 
 Then open your AI coding assistant and type:
 
@@ -235,7 +235,7 @@ graphify hook status
 # always-on assistant instructions - platform-specific
 graphify claude install            # CLAUDE.md + PreToolUse hook (Claude Code)
 graphify claude uninstall
-graphify codex install             # AGENTS.md (Codex)
+graphify codex install             # AGENTS.md + PreToolUse hook in .codex/hooks.json (Codex)
 graphify opencode install          # AGENTS.md + tool.execute.before plugin (OpenCode)
 graphify cursor install            # .cursor/rules/graphify.mdc (Cursor)
 graphify cursor uninstall