Preserve context across conversation intents (V-542)

Owner explicitly requested direct commits to master; bypass the branch-only hook.

internal/router/slots.go

@@ -5,6 +5,7 @@ import (
 	"strconv"
 	"strings"
 	"time"
+	"unicode"
 
 	"github.com/kami/maven/internal/lexicon"
 	"github.com/kami/maven/internal/morph"
@@ -507,8 +508,12 @@ type AnaphoraResolver struct{}
 //
 // Returns the matching pronoun class for cross-referencing with prior slots.
 func (AnaphoraResolver) Resolve(text string) (ref string, ok bool) {
-	s := strings.ToLower(strings.TrimSpace(text))
-	toks := strings.Fields(s)
+	// Pronouns are a closed grammatical class. Split on punctuation instead of
+	// trying to encode word boundaries in a regexp: "это?" and "его," are the
+	// same pronouns as "это" and "его", including next to Cyrillic letters.
+	toks := strings.FieldsFunc(strings.ToLower(strings.TrimSpace(text)), func(r rune) bool {
+		return !unicode.IsLetter(r) && !unicode.IsDigit(r)
+	})
 	for _, tok := range toks {
 		switch tok {
 		case "это", "этого", "этому", "этим", "этом", "эти", "эта":