Design: the inbox's ask cards use §5's card and buttons, and the ask-* classes leave §5d #3876

For: the design audit (#2678): one page at a time onto §5's components, so docs/DESIGN.md §5d only shrinks. One inbox, tap-through: the ask card is where the owner decides, and it should be the calmest card in the forge.

Done:

• [ ] The inbox's ask cards on /asked is drawn from §5's components (src/web/ui.ts helpers such as row, card, badge, btn, and §5 classes) in place of .ask-acts .ask-card .ask-group .ask-kind .ask-meta .ask-more-acts .ask-pick .ask-pick-hit .ask-short .ask-waiting, which src/web/style/content.ts defines today. Ship, decline and say still post from the card and stay on the page.
• [ ] Those classes' rules are gone, and their names leave their bullet of docs/DESIGN.md §5d. bun scripts/design-lint.ts passes, and so does --update with a lower or equal baseline.
• [ ] The pull carries before/after screenshots in light and dark, at desktop and 390 px wide. Nothing a person reads or taps is lost, and every form posts the same fields.
• [ ] The page's existing tests pass. A test asserts the old class names are absent from the page's HTML.

Files: src/web/studio/asks_page.ts, src/web/style/content.ts, docs/DESIGN.md, the page's test. Risk: another page borrowing one of these classes. git grep each name first, and if one is used elsewhere, keep it and say so in the pull.

Parked by the crew: the check failed ("GET /:owner/:name/milestones renders the pinned HTML") and the decider saw no point in another try (pull #3905 closed). Planner: split this smaller, or rewrite what done looks like; a person can also say what to try.

Parked by the crew: the check failed ("design check: nothing added outside the system (#2678) > the tree is no worse than its baseline") and the decider saw no point in another try (pull #4039 closed).

Parked twice since a person last spoke here, so it is the planner's now. Every reason:

1. the check failed ("GET /:owner/:name/milestones renders the pinned HTML") and the decider saw no point in another try (pull #3905 closed)
2. the check failed ("design check: nothing added outside the system (#2678) > the tree is no worse than its baseline") and the decider saw no point in another try (pull #4039 closed)

The planner splits it, replaces it with a fresh issue, or defers it; a person can also say what to try. Nothing starts here until then, and the board lists it.

Replaced by #4083, which waits for #4063 (the design check's baseline test parked it) and says how to treat a shared class without breaking the milestones page's pinned HTML.