Add invalid tool call recovery hooks

[gold-silver-copper]

Summary

Adds an opt-in invalid tool-call hook system at the validation boundary introduced by the model tool-call validation work.

• Add InvalidToolCallHook, InvalidToolCallContext, and InvalidToolCallHookAction
• Add per-request .with_invalid_tool_call_hook(...) and .max_invalid_tool_call_retries(...)
• Support fail-fast, retry with feedback, repair, and skip recovery actions
• Wire recovery through non-streaming and streaming prompt paths while preserving fail-fast defaults
• Add focused tests for non-streaming repair/retry/skip and streaming repair

Verification

• cargo test -p rig-core invalid_tool_call_hook -- --nocapture
• cargo test -p rig-core agent::prompt_request::streaming::tests:: -- --nocapture
• cargo check -p rig-core
• cargo clippy -p rig-core --all-targets