The extractive fallback runs when an LLM memory flush fails, so it is the last
thing standing between a session and losing its accumulated decisions. Its cue
patterns were English-only ("decided to", "prefer", "the API is"), which makes it
effectively inert for a session conducted in another language: it still returns a
non-empty result, so nothing looks broken, but the result is noise.
Measured on 195k characters of real Vietnamese session text: 9 decision matches
(all of them stray English fragments), 0 preferences, 0 technical facts — about
97% of what it "saved" was incidental file paths. After adding Vietnamese cues the
same corpus yields 21 decisions and 6 preferences on the largest session.
Adds parallel Vietnamese patterns for the same three categories and merges them
into the existing results with deduplication, so English extraction is unchanged
and mixed-language sessions get both. Tests cover Vietnamese-only,
English-only, and mixed histories, plus a guard that ordinary Vietnamese
narration is not misread as a decision or a preference.
Co-authored-by: nguyenha935 <nguyenha935@users.noreply.github.com>
