feat(copy): PR 1.1 — research-grounded copy + prompt corrections

Add cue-anchored "When [cue], [action]" framing to the task-decomposition
prompt where natural cues are present (Gollwitzer-style implementation
intentions, d=0.65 effect size). Soften Bionic Reading and accessibility-
font copy to honest preference framing per the v3 audit (Strukelj 2024;
Doyon n=2,074). Update timer nudge from "Still on that timer?" (which
read as judgmental) to "Timer's still running." Replace stale Tasks
page header copy promising automatic extraction.

Audio envelopes (focusTimer 20ms ramp, sounds.ts 10ms attack) verified
correct per memo §B; no code change needed.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

docs/brief/design-principles.md

@@ -6,7 +6,7 @@
 - **Fonts:** Lexend or Atkinson Hyperlegible Next as defaults. Clean sans-serif with large x-height. OpenDyslexic available as a user option but NOT recommended as default — peer-reviewed evidence (Rello & Baeza-Yates 2016; Kuster et al. 2018) shows it does not outperform standard sans-serif fonts. **Spacing is the active typographic ingredient, not letterform** (see Appendix A3). Italic text must never be used for extended reading — it significantly impairs reading in neurodivergent populations.
 - **Minimum 16px size, 1.5x line spacing, left-aligned text.** Maximum 75-character line width to prevent line-skipping fatigue.
 - **Variable font support.** Where possible, implement adjustable typographic axes (spacing, weight, width) so users can dynamically adapt typography to their own fluctuating visual-perceptual thresholds — not just choose between static font options.
-- **Bionic Reading toggle.** Optional mode that bolds the first few letters of each word to create artificial fixation points. Helps ADHD brains maintain reading momentum and prevents eyes from skipping lines. Increasingly popular accessibility feature — low implementation cost, high perceived value. Should be a toggle in settings, not default.
+- **Bionic Reading toggle.** Optional mode that bolds the first few letters of each word. Independent studies (Strukelj 2024; *Attention, Perception & Psychophysics* 2025; Doyon n=2,074) find no comprehension benefit and small reading-speed *costs* on average — but individual experience varies, and some users genuinely find it more comfortable. Offer as an honest preference toggle ("some people find this helps; the evidence is mixed"), default off, never marketed as "proven for ADHD/dyslexia". See `research-grounded-design-principles.md` §7.
 - **Rationale:** Decoding text consumes high metabolic energy for dyslexic or ADHD brains. Visual crowding affects both peripheral AND central (foveal) vision in these populations. Every typographic decision should reduce that metabolic cost.
 
 #### Colour system