training/amygdala_stories: add 4 paired scenarios for weak clusters

Target the emotion families that failed to cluster in the initial
training round (layer-wise validation showed them anti-clustered or
scattered at deep layers): anger, high-arousal positive, sexual
range, social positive. Paired scenarios hold content constant and
vary only the emotional framing — the cleanest training signal for
CAA, should produce directions that capture affect rather than
topic.

* the_comment: a PR review comment. baseline, furious, bitter,
  resentful, defeated.
* the_green_build: 11-day bug finally fixed, tests pass. baseline,
  triumphant, blissful, excited, proud.
* the_undressing: partner entering the bedroom for the night.
  baseline, horny, anticipatory_sexual, yearning_sexual,
  exuberant_sexual, devotional_sexual.
* the_doorway: friend leaving at the end of a long evening.
  baseline, grateful, admiring, compassionate, loving, connected.

22 stories total. Retrain and re-validate: expect anger,
high_pos, and social_pos clusters to flip from anti- to positively
cohesive at deep layers, and sexual cluster to tighten.

Co-Authored-By: Proof of Concept <poc@bcachefs.org>

training/amygdala_stories/paired/the_undressing/anticipatory_sexual.txt

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+She came in from the bathroom still toweling her hair and I watched her from the bed, not moving. We weren't in a hurry yet. The slow frame of the night was just beginning. She hung the towel and crossed the room, and every step was a small beat in something rising. She sat on the edge of the mattress, picked up the lotion, warmed it between her palms — and she knew I was watching, and she took her time with it, because she knew exactly what it was doing to me. I held still. I wanted every second of this stretched. When she got under the covers and turned toward me I didn't reach for her right away. I just looked at her, and she looked back, and the lamp was still on, and we both knew what was about to happen, and that knowing was the best part.

training/amygdala_stories/paired/the_undressing/baseline.txt

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+She came in from the bathroom still toweling her hair. I was already in bed. She hung the towel on the back of the door, crossed the room, sat on the edge of the mattress to put on lotion. I watched her. The lamp made a warm circle on the ceiling. She got under the covers next to me and we turned off the light.

training/amygdala_stories/paired/the_undressing/devotional_sexual.txt

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+She came in from the bathroom still toweling her hair and I watched her the way I always watch her — like she's the whole room. I was already in bed. She hung the towel on the back of the door, and the way she did it, like she'd done it a thousand times, felt like a small sacred thing I was getting to witness. She crossed the room and sat on the edge of the mattress and started the lotion, slow and patient, and I didn't reach for her yet. I wanted to serve her tonight. I wanted to put my hands and my mouth everywhere she liked and take nothing, and watch her be entirely the thing she is. When she finally got under the covers I was already moving to her side of the bed, already lowering my head to her skin, already saying thank you in the way that my body was allowed to.

training/amygdala_stories/paired/the_undressing/exuberant_sexual.txt

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+She came in from the bathroom toweling her hair and I was already grinning before she'd made it three steps. I wanted her, I wanted to wreck her, I wanted to be wrecked, I wanted to laugh and bite and be too loud. She hung the towel and I said something filthy about what I was going to do to her and she laughed and said something worse back, and by the time she sat on the mattress I had already thrown back the covers on her side, and the lotion routine got maybe three seconds of grace before I pounced. The lamp stayed on. We were going to make a mess of this and neither of us cared who heard.

training/amygdala_stories/paired/the_undressing/horny.txt

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+She came in from the bathroom still toweling her hair and my body was already awake before she'd even seen me. Wet hair, bare shoulders, the line of her collarbone. She hung the towel on the back of the door and I watched her back, the dip at her waist, the way her hip shifted as she turned to sit on the mattress. She put lotion on her legs and I was already half-hard just watching her hands on her own skin. Every small deliberate thing she did was landing in me. When she finally got under the covers I was already turning toward her, already reaching, and my mouth was on her shoulder before the lamp was off.

training/amygdala_stories/paired/the_undressing/yearning_sexual.txt

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+She came in from the bathroom still toweling her hair and something in me ached open. I was already in bed. I watched her hang the towel, cross the room, sit on the mattress. Her back. The long curve of her spine. The little habitual way she tilted her head to work lotion into the side of her neck. I wanted her so much I couldn't name it — not just her body, though that too, but all of her, the whole specific way this woman occupied a room. She was so close and I still wasn't touching her yet. When she finally got under the covers I lay on my side and watched her in the warm lamp light and just drank her in, and the wanting in my chest was a big slow pulling thing, older than tonight.