fix(design): the four trust-critical pages — honest states, legible status, house palette #5540

Design Wave A, part 1 (agent-built, render-proven over CDP before commit)

1. DORA stops defaming us: root cause — the page reads deployments, populated only by the Vapron webhook path; self-hosted repos deploy via the timer and never write there. Zero rows all-time now renders "Not measured — deploy tracking is not wired for this repository" (neutral, no red badge, no 0.0) — and a latent false-green died with it (worstLevel() of four nulls returned "Elite"). Wired-but-quiet repos still show real numbers; DB errors say "unavailable", never "not wired".
2. Bus-factor zero-scan renders "No analysis yet" with the true predicate (≥3 commits per file), never the green all-clear — pinned by a new 5-test file.
3. Security "All clear" banner legible in light (the pale literals were dark-era choices; now color-mix green tints per the house idiom).
4. nl-search re-paletted evergreen (16 → 2 literals, markup untouched) and login made real: dark was inert because the view hardcoded data-theme="light" with a literal-only stylesheet — now token-driven with the theme cookie resolved in the handler (additive pass-through in auth.tsx), evergreen primary CTA, dead desktop band closed, two indigos killed.

Typecheck clean · 131 adjacent tests green · design-audit: touched files 101 → 62 literals, zero banned · all five pages screenshot-verified light+dark.

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