fix(factory): bundle phase one guide context

[walker-tx]

Summary

Eliminate model-authored Phase 1 file discovery after the Box refresh failed on a quoted shell glob. A deterministic helper now validates the target path and bundles authority, role, schema, persona, representative-guide, and target-artifact context.

Safety and verification

• exact four-file target boundary; symlinked targets/artifacts rejected
• only complete physical guides count as representatives
• checked discovery and cleanup-managed temporary files
• bounded handling for large Kit spill artifacts
• factory suite: 11/11 passed
• ShellCheck 0.10.0 and actionlint 1.7.7 passed
• independent review approved
• no paid model or research calls used