feat(term-maps): move directory rules into Settings

[kfstorm]

Summary

Move persistent directory Term map settings into Settings so Translate focuses on the Term map choice for the current Job. Directory edits previously appeared beside Media selection and looked too similar to a one-off translation choice.

• Keep one optional selector in Translate for automatic selection, a specific Term map, or no map. Show the resolved automatic result without ancestor-directory details.
• Split Term map settings into a searchable library and an Automatic use view for explicit directory rules. Show creation guidance and JSON import only in the new-map flow.
• Preview the fallback before deleting a directory rule and report the resulting automatic choice. Require fresh rule data for deletion and retries.
• Preserve translation drafts across Settings navigation in memory. Require a new choice if a selected Term map is deleted, and keep explicit no-map selection available during loading or errors.
• Resolve file-link directories consistently between previews and Job creation, and update the interface copy across all supported languages.

API and behavior

Add GET /api/term-maps/directory-rules to list explicit directory settings. Discovery responses include the resolved Media directory while retaining the requested Media path.

Each Job uses at most one complete Term map. Child directory rules replace the ancestor's choice without merging entries, and batch translation retains its same-directory constraint. Existing directory settings and queued Job snapshots are preserved; no database migration is required.