vocab: stop re-teaching a word later in the same session (239 tags)

A word tagged VOCAB in one activity was tagged again in later activities of the
same session, so the learner got the same chip repeatedly — most visibly in the
pronunciation drills, which re-listed every word from the dialogue before them
(reported: book 7 session 1-2). Rule applied: drop a VOCAB whose word was
already tagged in an EARLIER activity of that session. Repeats INSIDE one
activity are kept — those teach distinct senses ('stuck to his finger' vs
'stuck the milk in the fridge', 'shop' as verb then noun). Also dropped chips
for plurals of already-known words in book 7 session 1-2, where the drill
teaches the singular/plural pair rather than new vocabulary. No session lost
all of its vocabulary (verified).

Co-authored-by: Cursor <cursoragent@cursor.com>

book-4-lesson-1.module

@@ -131,10 +131,8 @@ REPEAT
 VOCAB: like to
 LINE: Joe likes to play baseball. {st-page_007_001.jpg}
 
-VOCAB: ball
 LINE: The children like to play with a ball. {st-page_007_002.jpg}
 
-VOCAB: game
 LINE: Kate and Sue like to go to football games. {st-page_007_003.jpg}
 
 LINE: Mr. and Mrs. Adams like to watch games on television. {st-page_007_004.jpg}
@@ -322,7 +320,6 @@ INTRO: You'll see a map of Texas. Listen and repeat the sentences about its citi
 INSTRUCTION: Listen and repeat.
 REPEAT
 
-VOCAB: city
 LINE: The city of Houston, the city of Dallas, the city of San Antonio. {bk04-l1a-f5-01.mp3}
 
 VOCAB: town
@@ -344,7 +341,6 @@ REPEAT
 VOCAB: live
 LINE: I live in the city.
 
-VOCAB: town
 LINE: My friend George doesn't live in a city. He lives in a small town.
 
 VOCAB: restaurant
@@ -405,7 +401,6 @@ LINE: They live in the small town of Castroville.
 
 LINE: Every month, they come to the city and visit Joe.
 
-VOCAB: visit
 LINE: Their visit always starts on a Friday and ends on a Sunday.
 
 LINE: On Saturday nights, they go to a good restaurant. {st-page_010_001.jpg}
@@ -917,7 +912,6 @@ INTRO: Mr. Green worked late yesterday. Today — again. His children may have f
 INSTRUCTION: Listen and repeat the sentences.
 REPEAT
 
-VOCAB: again
 LINE: Mr. Green worked late yesterday. Today he's working late again.
 
 LINE: Last week I watched the Los Angeles Show. Yesterday I watched the show again.