hq-hcil1: Remove deprecated HasConflict/HasAuthFailure/IsNotARepo/HasRebaseConflict
methods that violated ZFC by having Go code decide error types based on stderr parsing.
Changes:
- Remove deprecated helper methods from GitError and SwarmGitError
- Export GetConflictingFiles() which uses git porcelain output (diff --diff-filter=U)
- Update CheckConflicts(), engineer.go, and integration.go to use GetConflictingFiles()
- Update tests to verify raw stderr is available for agent observation
ZFC principle: Go code transports raw output to agents; agents observe and decide.
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
f7d497ba07