docs: add model_id to before_llm_call hook payload documentation

[aheritier]

Summary

The before_llm_call hook payload includes a model_id field — this is documented in the code (types.go:177-186: "ModelID identifies the model the runtime is about to call (for before_llm_call) or just called (for after_llm_call)") and confirmed in hooks.go:424-430.

However, docs/configuration/hooks/index.md only lists iteration for the before_llm_call table row, omitting model_id.

Fix needed

In the hook payload table, update the before_llm_call row from:

| `before_llm_call` | `iteration` — 1-based run-loop iteration counter |

to:

| `before_llm_call` | `iteration` — 1-based run-loop iteration counter; `model_id` — the model about to be called |

Context

Discovered during review of PR #2923 (which fixed model_id for after_llm_call). The before_llm_call omission pre-dates that PR.

[aheritier]

Triage summary

Category	Classification
Type	docs
Area	hooks / configuration
Priority	low
Good first issue	✅ yes

The issue identifies a specific, well-scoped documentation gap: the before_llm_call hook payload table in docs/configuration/hooks/index.md is missing the model_id field, which is already present in code (types.go, hooks.go) and was documented for after_llm_call in PR #2923. The fix is a one-line update to the docs table.

[aheritier]

This was fixed in PR #2927, which added to the payload table row and included a note explicitly documenting for both and . Closing as resolved.