Fix YAML replacement affecting wrong fields with same value

[ChrisJBurns]

Summary

• Fix bug where updating one YAML field would accidentally modify another field with the same value but different formatting
• Make replacement patterns key-aware to target only the specific field being updated
• Add regression tests covering the version/appVersion scenario

Problem

When a Chart.yaml has both version: 0.9.0 (unquoted) and appVersion: "0.9.0" (quoted), updating the version field would accidentally modify appVersion first because the double-quoted regex pattern matched before the unquoted pattern.

This caused the toolhive release workflow to fail with:

Error: version mismatch in deploy/charts/operator-crds/Chart.yaml at path appVersion: 
expected to find "0.9.0" but found "0.9.1"

Root Cause

The surgicalReplace function searched the entire file for pattern matches, not just the value at the target path. When patterns like "(0\.9\.0)" were tried, they matched the quoted appVersion even when we wanted to update the unquoted version.

Solution

1. Extract the key name from the YAML path (e.g., metadata.version → version)
2. Include the key in replacement patterns so they only match the specific field:
   • Before: "(0\.9\.0)" (matches any quoted 0.9.0)
   • After: (version:\s*)"(0\.9\.0)" (only matches version's quoted value)
3. Fix Go regex $1 syntax by using ${1} to avoid ambiguity when versions start with digits

Test plan

• Added TestUpdateYAMLFile_SameValueDifferentKeys with 4 test cases covering:
  • Update unquoted version without affecting quoted appVersion
  • Update quoted appVersion without affecting unquoted version
  • Sequential updates to different keys with same value
  • Nested paths with different keys
• Added TestExtractKeyFromPath for the new helper function
• All existing tests pass

🤖 Generated with Claude Code