fix(web): scale avatar initials with zoom, wire up the px-text guard

[TheSeydiCharyyev]

Summary

PubkeyAvatar pins its small-size initials to text-[10px]. The disc around them (h-6 w-6) is rem-based, so browser zoom scales the disc while the initials stay at 10 physical px — the glyphs shrink relative to their box as the user zooms in. That is the freeze-against-zoom problem the shared px-text guard exists to catch.

Nothing caught it because web never wired that guard up. Web runs two of the three shared guards in scripts/ — check-file-sizes-core and check-pubkey-truncation-core — but not check-px-text-core, even though that core is written for multiple apps and takes a per-app overrides allowlist just like the other two.

This change:

• adds a 2xs font-size token (0.6875rem / 11px) to web/tailwind.config.js, mirroring the desktop token of the same name;
• uses text-2xs in PubkeyAvatar instead of the text-[10px] literal;
• adds web/scripts/check-px-text.mjs and wires check:px-text into web's check chain, so arbitrary text-[…px] / text-[…rem] literals cannot drift back in.

The allowlist is empty on purpose — web has no fixed-size display glyphs of the kind desktop exempts (avatar emoji, onboarding titles).

Related issue

None found. I searched open issues and the changed-file list of every open PR: none touch web/package.json, web/tailwind.config.js, web/scripts/ or web/src/features/repos/ui/PubkeyAvatar.tsx.

Testing

web package on Windows 11, node 22.17.1, pnpm 11.4.0.

• With the text-[10px] literal restored, the new guard fails on it: Web px-text check failed: src/features/repos/ui/PubkeyAvatar.tsx:20: text-[10px].
• With the token in place, pnpm check passes all four steps (biome, file sizes, px-text, pubkey truncation), pnpm typecheck is clean, and pnpm build succeeds.
• Confirmed the token actually resolves rather than silently emitting nothing: the built stylesheet contains .text-2xs{font-size:.6875rem}. Without that check a missing token would leave the initials at an inherited size, which would look like a fix while being a regression.

[TheSeydiCharyyev]

CI is green here: 21 checks pass and the rest skip on path filters. The Web job ran the new check:px-text guard, so the wiring this PR adds is already exercised by the repo's own pipeline.

Still applies to current main: web/package.json has no check:px-text, web/tailwind.config.js has no sub-text-xs token, and PubkeyAvatar still uses text-[10px] — which stays at 10 physical px while the h-6 w-6 disc around it scales with browser zoom.

[TheSeydiCharyyev]

CI is green here: the full matrix ran on 2026-07-29 and passed, including the Web job that exercises the check:px-text guard this PR adds. There are no review comments yet. I can rebase or narrow the change if that is useful.