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-6-lesson-2.module

@@ -88,7 +88,6 @@ VOCAB: helicopter
 VOCAB: blade
 LINE: This is a helicopter. The blades help a helicopter fly. {st-page_040_001.jpg}
 
-VOCAB: jet
 VOCAB: to travel | travel
 LINE: Capt Miller flies Air Force jets. Sometimes he travels to other bases in one of the planes. {st-page_040_002.jpg}
 
@@ -106,7 +105,6 @@ VOCAB: to get | get
 VOCAB: got
 LINE: I get to work by bus. I got to work late this morning.
 
-VOCAB: home
 VOCAB: house
 LINE: This is a house. It's the home of the Adams family. {st-page_041_001.jpg}
 
@@ -233,13 +231,10 @@ LINE: Lt Lamb's plane gets in at 12:00 noon.
 LINE: My brother got in late last night.
 LINE: It was snowing last night. His plane didn't get in.
 
-VOCAB: get on
-VOCAB: get off
 LINE: You get on and get off the bus at the bus stop.
 LINE: You can get off the train at the next town.
 LINE: When can we get on the plane?
 
-VOCAB: without
 LINE: Do you want coffee with or without sugar?
 LINE: You may go without me. I don't want to go.
 LINE: Take your I.D. card with you. You can't get in the commissary without it.
@@ -963,15 +958,12 @@ LINE: I know he's here. I'm sure.
 LINE: He'll leave tomorrow. That's for sure.
 LINE: Do you want to go? Sure.
 
-VOCAB: later
 LINE: Will you come back later? Yes, I'll return in an hour.
 LINE: Okay, see you later.
 
-VOCAB: delicious
 LINE: The food in this restaurant is good. It's delicious.
 LINE: The chicken was delicious.
 
-VOCAB: awful
 LINE: The French fries at the snack bar are awful. They're bad.
 LINE: The weather was bad yesterday. It was awful.