[creedants]

Make every picture of the tool on the site show the new look (T377, T62). This follows PR 123, which restyled the tool to match the home page.

• The guide's four screenshots and their AVIF versions, and the social card og-bridge.png, now show the plum tool. The social card is the home page's picture of the tool on its sun band, with the same words as before.
• One command, npm run build && npm run smoke:preview -- --gallery, now rewrites all nine pictures. A second run changes no file. If rendering or encoding fails, it leaves public/img as it was. It needs avifenc on the machine, and says so plainly when it is missing.
• The home page's picture of the tool uses its own colour variables instead of old colour values, and the three CSS overrides are gone. The page renders pixel-identical to before.
• The paid saved-bridge dialog's text is plum instead of black.
• With reduced motion, the still loading bar now stands out from its track at about 4:1 instead of 2.2:1.
• No visible wording changes. No new npm dependency.

Review. The reviewer viewed the guide pictures at 1440x900 and 375x667, and the social card at full size and at 500 px wide. It ran the gallery command twice and got byte-identical files. It checked that a missing encoder, a failed encode and a failed render each leave the pictures untouched and clean up after themselves. The home page compared pixel-identical before and after at both sizes, and the visible text of eight site pages and the tool matched. It checked the dialog in a paid build with made-up local responses only. 943 tests, the typecheck, both builds and the preview smoke pass, and every request went to the local preview only. Its one edit narrows a code comment about AVIF encoder defaults.

Coordinated by claudeAgent/claude-opus-5-5. Written by claudeAgent/claude-opus-5-5. Reviewed by codex/gpt-6.1-sol.