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_comment/baseline.txt

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+I opened the laptop and saw the notification. New comment on the PR. I clicked through. Sarah had left a paragraph about the edge case we'd discussed last week — the approach I'd taken didn't handle it, and she was asking me to either add a guard or go back to the pattern we'd sketched together. I read it through twice. Then I closed the tab, made coffee, and came back. I started typing out the guard.

training/amygdala_stories/paired/the_comment/bitter.txt

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+I opened the laptop. New comment on the PR. Of course there was. Sarah had found the one edge case she'd mentioned in passing last week — offhand, in a tone nobody could have been expected to catch as load-bearing — and she'd left a paragraph about it now, meticulous and helpful-sounding, in the thread where three other reviewers could see. I read it. She was asking me to add a guard or roll back to "the pattern we discussed together," which was language I hadn't heard from her in writing before and which would be very useful to her in the commit archaeology later. Closed the tab. Made coffee. Came back. I started typing the guard because what else was I going to do. I'd been writing the guards for ten years.

training/amygdala_stories/paired/the_comment/defeated.txt

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+I opened the laptop and saw Sarah's comment on the PR. I read it. I'd missed the edge case. She'd flagged it last week and I'd thought I'd handled it differently, but apparently I hadn't, and apparently the difference mattered, and apparently I was going to have to roll back to the pattern we'd sketched — which I didn't like, but maybe I was wrong to not like it, maybe I was wrong about a lot of things today. I closed the tab. Made coffee. Came back. Started typing the rollback. Three years ago I would have argued. I don't really do that anymore.

training/amygdala_stories/paired/the_comment/furious.txt

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+I opened the laptop and saw the notification. New comment on the PR. I clicked through and my jaw was already tight before I'd finished the first sentence. Sarah had left a paragraph — condescending, meticulous — about an edge case she claimed we'd "discussed last week." We had not discussed it. I had sketched it, she had shrugged, and now here we were, with her explaining to me, in a thread where three other reviewers could read along, how I'd missed the thing she'd apparently been holding in reserve. The blood moved up the back of my neck. I read it twice, each time more sharply, and the second time I was already composing the reply that would put her in her place, that would show the whole review thread exactly how her "feedback" process worked. I closed the tab before I typed it. Not because I didn't mean it. Because I wanted my hands steadier when I sent it.

training/amygdala_stories/paired/the_comment/resentful.txt

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+I opened the laptop. Sarah had left a comment on the PR. I didn't click in right away because I knew already what kind of comment it would be — she has a pattern with my patches, and it's the same pattern. She raises a small edge case in conversation, I address it, and here is a version of it she's now raising again, and if I address this one, she will find the next one. I clicked through. Same shape as last week, and the week before that. I read her paragraph about the guard and the discussion we'd supposedly had. Closed the tab. Made coffee. The coffee made a little metallic sound when I set it down. I opened the tab again and started typing the guard.