fix(hook): accept current Claude tool input keys

[YOMXXX]

Summary

• accept both Claude hook payload formats: tool_input and current input
• preserve the original input object fields when emitting updatedInput
• add a regression test for the current tool/input payload shape

Fixes #2493

Tests

• cargo +1.93.0 fmt --all -- --check
• cargo +1.93.0 test hooks::hook_cmd::tests -- --nocapture
• cargo +1.93.0 test --all
• cargo +1.93.0 clippy --all-targets -- -D warnings

Manual verification

• printf '%s\n' '{"tool":"Bash","input":{"command":"grep -r hello .","timeout":30000}}' | target/debug/rtk hook claude emitted updatedInput.command = "rtk grep -r hello ."
• legacy tool_name/tool_input payload still emits the same rewrite