fix: support git -C <path> in rewrite registry

[ousamabenyounes]

Summary

• Fixes rtk rewrite not recognizing git -C <path> <subcommand> commands
• Updates regex pattern to accept -C and -c flags before the git subcommand using a non-capturing group (?:-[Cc]\s+\S+\s+)*
• Adds 4 tests: rewrite with -C for status/log/diff + classify verification

Before / After

# Before (exit 1, no rewrite):
rtk rewrite 'git -C /tmp status'        # → nothing

# After:
rtk rewrite 'git -C /tmp status'        # → rtk git -C /tmp status
rtk rewrite 'git -C /tmp log -5'        # → rtk git -C /tmp log -5
rtk rewrite 'git -C /tmp diff --name-only' # → rtk git -C /tmp diff --name-only

Test plan

• 4 new tests for git -C support (rewrite + classify)
• 156 existing registry tests still pass
• git diff --cached not broken (non-capturing group preserves subcommand extraction)
• Manual verification with cargo run -- rewrite

Closes #555

🤖 Generated with Claude Code

[aeppling]

Code Review — PR #556

Clean, well-scoped fix. 2 files, +43/-1, no unrelated changes. The regex change is backward compatible (zero-or-more match).

Verdict

Minimal, correct, non-breaking.

[aeppling]

Benchmark cicd failed , need to be fix

[aeppling]

Closing this PR and merging #547

[aeppling]

#547