Text ads: require self-contained lines

Each line gets its own emoji bookends, so a sentence running across lines
reads as broken rather than as three fragments.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

suite-textads.js

@@ -165,7 +165,8 @@ async function generate(opts) {
     'HARD LENGTH LIMITS (count every character, spaces included — going over makes the ad unusable):\n' +
     '- SUBJECT: at most ' + SUBJECT_BUDGET + ' characters.\n' +
     '- L1, L2, L3: at most ' + LINE_BUDGET + ' characters EACH.\n' +
-    'These are extremely short. Think billboard, not sentence. Fragments are good. L3 should be a short call to action.\n\n' +
+    'These are extremely short. Think billboard, not sentence. Fragments are good. L3 should be a short call to action.\n' +
+    'EACH LINE MUST STAND ALONE. Every line is decorated separately, so a sentence must never run on from one line into the next. "Get two and teach / them to do the / SAME THING" is WRONG. Three self-contained fragments is RIGHT.\n\n' +
     'Write ' + ask + ' different ads. Vary the wording and the hook across them. Output EXACTLY this shape and nothing else:\n\n' +
     'AD 1\nSUBJECT: <text>\nL1: <text>\nL2: <text>\nL3: <text>\n\nAD 2\nSUBJECT: <text>\nL1: <text>\nL2: <text>\nL3: <text>\n\n(and so on)';