Eliminate N+1 queries in character-order display and editing

[DeusExTaco]

Summary

I eliminated the per-character database queries in character-order display and editing flows.

• Bulk-load character identity and alias relationships once per display/edit operation.
• Bulk-load character-order through rows instead of calling get() for each appearance.
• Batch removals, updates, and inserts in the character-order editing view.
• Preserve ordering and alias/civilian display behavior.

Testing

• apps/oi/tests/db/test_character_order_revision.py: 7 passed
• Story/revision compatibility suite: 71 passed
• Added query-bound regression coverage for display and edit preparation.

Closes #731

[gemini-code-assist]

Code Review

This pull request optimizes character and story-character ordering queries by introducing a bulk-loading cache (_build_character_identity_cache) for alias and civilian identities, and by batching database operations (using bulk_create and bulk_update) during character reordering. These changes significantly reduce the number of database queries. However, a critical bug was identified in apps/gcd/models/story.py where querying story_character__story_character_id instead of story_character_id for character revisions causes ID mismatches and breaks the editing flow.