1A: refined clip timings (cue trimming, gap compression), 512px recomposed images, four Figure-8 panels, activity-wide Figure-5 map; SHOW_PROMPT migration + INTRO fixes for remaining lessons

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

lesson-3C.module

@@ -13,7 +13,7 @@ VOICE: Narrator | gacrux
 
 $LESSON Figure 1
 $DIALOGUE
-INTRO: Look at figure one look at the dialogues and repeat the underlying word well. Now listen to the dialogues.
+INTRO: You're going to hear some short dialogues with new words. Repeat the new words, then listen to the dialogues.
 REPEAT
 
 VOCAB: well
@@ -46,7 +46,6 @@ Beth: No, we're not. I don't like Bob very well. {bk04-l3c-f1-13.mp3}
 $LESSON Figure 2
 $SELECT Tap the correct answer
 INSTRUCTION: Listen to the statement and tap the correct option.
-AUDIO_ONLY
 
 EXAMPLE
 PROMPT: Lt. Lee is a good student. {bk04-l3c-f2-01.mp3}
@@ -193,7 +192,6 @@ RESPONSE: No, he can't read it very well. {bk04-l3c-f6-10.mp3}
 $LESSON Figure 7
 $SELECT Choose the true statement
 INSTRUCTION: Listen to the paragraphs and tap the true statement.
-AUDIO_ONLY
 
 PROMPT: Paragraph 1 {bk04-l3c-f7-01.mp3}
 OPTION: a | Ken lives in a small town.