feat(about): rebuild the About box as a conversion surface

Creator: the About box was "shitty" — an unreadable logo, a version number nobody asked for, copy that
insulted the creator, and buttons that looked like text. Rebuilt around one job: convert.

- **820×860 modal** (was 650×700) with a scrollable hub, and the logo at **520 px wide** instead of
  125 — the asset is 2816×1536, so it was being drawn as a thumbnail, not an icon problem.
- **Pre-Release pill** replaces "Version 1.0.0" (the assembly version stays in log lines). The pill is a
  button: it opens llamacasty.com until a Steam store page exists, so the link changes in one place.
- Tagline: "1-2-3, and go live to the world on YouTube!" The old "simple enough that even the most
  right-brained person can intuit it" is gone, and a test asserts it stays gone.
- The offer in three short blocks (free 30 fps · paid 60 fps · one-time, lifetime, no account /
  subscription / tracking), then the launch price and **one primary CTA**: "Unlock 60 fps — $79".
- Price: $79 until **April 1, 2027**, then $99 locked for life. The numbers live once, in
  `MainViewModel.Overlays`, and are recorded in `docs/ai/commercial.md`.
- **A paying customer is never sold to**: ownership collapses the price/CTA block and shows
  "Licence: owned via Steam — thank you."
- Secondary destinations (channel, Mastodon, coffee, licences) are one quiet row; footer is
  `© Llama Chile Shop`; the "Made by gramps" line is removed.
- `YtButtonSecondary` now carries a higher surface, a hairline border and a keyboard focus ring — they
  were the same tone as the panel behind them, which is why they read as plain text.

Test: `AboutHubTests.About_ShowsTheOfferToFreeUsers_AndNothingToSellToOwners` — tagline, pill, price,
CTA text, copyright, the removed lines stay removed, and the CTA block collapses when owned.
FAST gate: 540 passed, 0 failed, 0 warnings.

docs/ai/ui-surface.md

@@ -1,3 +1,17 @@
+## About box (2026-11-05)
+
+A conversion surface, not a credits page: **820×860 modal**, ~520 px logo, a `Pre-Release` pill that is
+itself a button (links to llamacasty.com until a Steam store page exists), the tagline
+"1-2-3, and go live to the world on YouTube!", the offer as three short blocks (free 30 fps · paid
+60 fps · one-time/lifetime/no-tracking), then the launch price and **one primary CTA**
+("Unlock 60 fps — $79"). Secondary destinations are one quiet row; the footer is `© Llama Chile Shop`.
+
+**A paying customer is never sold to:** with ownership verified the price/CTA block collapses and is
+replaced by `Licence: owned via Steam — thank you.` The old tagline ("simple enough that even the most
+right-brained person can intuit it") and the "Made by gramps" line are gone for good.
+`YtButtonSecondary` carries a higher surface, a hairline border and a keyboard focus ring — before this
+the secondary buttons were the same tone as the panel behind them and read as plain text.
+
 ## Left panel alert stack (2026-11-05)
 
 A stack of red rows at the top of the left panel, **above both mode grids** (so it shows while editing