## Summary
V2 profiles add both `config.toml` and `<profile>.config.toml` to the
config stack. Because both user layers resolve hook discovery to the
same Codex home, Codex loaded the same `hooks.json` twice. This
duplicated hook rows and caused each matching command to run twice.
Deduplicate JSON hook discovery by absolute config folder within each
effective config stack. TOML hooks remain layer-specific, and multi-cwd
`hooks/list` results remain independently resolved per cwd.
## Reproduction
1. Add `config.toml` and `work.config.toml` under `$CODEX_HOME`.
2. Add one command hook to `$CODEX_HOME/hooks.json`.
3. Run Codex with `--profile work`.
4. Trigger the hook.
Before this change, one declaration creates two handlers. Afterward, it
creates one.
Fixes#25645 and addresses the single-cwd duplication in #25437.
## Validation
- `cargo nextest run -p codex-hooks`
- `just fix -p codex-hooks`
- `just fmt`
- `just argument-comment-lint -p codex-hooks`
AbhinavandGitHub
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