The translate card, pointed the other way, and a call that no longer happens

Phase 28's step (b): both remaining items are about direction, and both had
a wrong answer that looked right.

isTranslation could not simply be read backwards. readsAsEnglish is a
deliberately low bar — Latin letters, not swamped by another script — which
every Portuguese sentence clears as easily as English does, so swapping its
two halves would have called every genuine Portuguese correction inside a
Portuguese document a translation. The flipped direction uses sentenceLang
from doclang.go instead, where English has its own curated marker list and
has to out-evidence the pair language to win. The English-document path is
untouched; reconcilePending carries the verdict to ask the question the
right way round.

The tap-through's whole observable change is a model call that stops
happening. /suggestions/{id}/translate now recovers the explanation's
language by re-running targetFor rather than assuming the pair, which gives
today's answer everywhere except the case that was broken: the Portuguese
writer whose explanation already arrived in Portuguese, previously
round-tripped through the model into Portuguese again. It answers "" there,
and the client's existing `res.translation.trim() || explanation` fallback
seeds the bubble with the explanation itself — no frontend change at all.
It deliberately does not render that explanation into English on the
grounds that English is technically the other half: an unasked-for
rendering into the language she is practising is noise, not a seed.

Tests pin both directions of the detector, with Portuguese-in-Portuguese as
the case the file exists for, plus four handler tests through the real
/check and /translate paths — including the skipped seed asserting the
model was never called, and the learning_pair zh learner whose English
explanation still renders into Chinese.

Left of the phase: (c) the garden's language tagging and read-aloud.

Claude-Session: https://claude.ai/code/session_01GJHNvirh7Hzhc9RL3HAvz7

internal/suggestions/reconcile.go

@@ -131,10 +131,12 @@ func reposition(tx *sql.Tx, row pendingRow, from, to int, chunkHash string) erro
 // collocation coach — where every row is up for re-proposal because the model
 // just re-read everything.
 //
-// `pairLang` is the writer's own language, needed only to type a finding that
-// turns out to be her language rendered into English (see language.go).
+// `pairLang` is the writer's own language and `docLang` this document's language
+// verdict; between them they type a finding that turns out to be one language
+// rendered into the other, in whichever direction this document makes useful
+// (see language.go).
 func (h *Handler) reconcilePending(
-	docID, contentText, pairLang string,
+	docID, contentText, pairLang, docLang string,
 	raw []llm.RawSuggestion,
 	scope pendingScope,
 	chunks, fresh []chunk,
@@ -235,7 +237,7 @@ func (h *Handler) reconcilePending(
 		typ := scope.forceType
 		if typ == "" {
 			typ = normalizeType(s.Type)
-			if isTranslation(s.Original, s.Replacement, pairLang) {
+			if isTranslation(s.Original, s.Replacement, pairLang, docLang) {
 				typ = db.SuggestionTypeTranslate
 			}
 		}