Introduce a `ru_en` FTS configuration (english_stem over ascii token
classes, russian_stem over Cyrillic ones) and flip every stored + query
side to it IN LOCKSTEP (acceptance #13):
- new migration creates ru_en, swaps the pages.tsv trigger + reindexes
existing rows (row-lock UPDATE, no ACCESS EXCLUSIVE), and swaps the
page_embeddings.fts generated column (documented rewrite/lock trade-off
for large tenants, mirroring the #443 trgm migration). down() reverts
tsv/fts to english BEFORE dropping the config (dependency order).
- page-embedding.repo.ts hybridSearch query config english -> ru_en, so
the RAG lexical leg's query config matches its fts column config.
- search.service.ts current query literals english -> ru_en so the column
and query configs stay paired (this commit is independently revertable;
the engine itself is rewritten in the A2-A9 commit).
The reindex is atomic within the single migration transaction (this repo's
Migrator wraps all pending migrations in one tx), so no morphology-desync
window exists and no dual-config read path is needed.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
agent_coder
4bfa2b59a1