The home feed's cards draw §5's card, row and btn, and the .fcard-* classes leave feed.ts's markup #4279

The home feed's cards in src/web/studio/feed.ts no longer emit any .fcard-* class. The type check, bun scripts/design-lint.ts and the design-lint, home-walk, feed-page, home-feed and studio tests pass, as does the new test. I did not run the full suite; the forge runs it on this push.

Each part now uses the §5 component that fits:

• Who: a plain <strong> in the card's head, next to avatar, nameMark and the kind badge.
• Text: a <p class="break">, so long unbroken text still wraps.
• Why: <p class="small muted break">.
• Reply: <p class="small break" data-placement>, with its #N links unchanged.
• Thought text: <p class="break"> with each line escaped and a <br /> between lines. .fcard-text used to keep line breaks with white-space: pre-wrap, so runs of spaces are no longer preserved.
• Reply and decide forms: <form class="stack"> with .input on the textarea. The submit btn sits in a .bar so it keeps the 44px touch height. The forms post the same fields to the same actions, and the textarea keeps maxlength="2000".
• Dismiss and mute: unchanged.

Not done:

• Not touched: the stylesheet rules and docs/DESIGN.md, as asked. Part two removes them.
• field() not used: it drops maxlength on a textarea and adds a visible label, so the textarea is a bare .input instead.
• row() not used: it is an <li>, which doesn't fit inside a card.
• flow_card.ts untouched: it still uses fcard-reason and fcard-unblock. It is outside this issue's file list.

Tests:

• New test/feed-card-markup.test.ts asserts no fcard- appears in a post or a thought. It also checks the words, links, forms, escaping and line breaks are still there.
• I changed test/home-walk.test.ts, whose assertion matched fcard-who">scribe</strong; it now matches <strong>scribe</strong. That test was tied to the old class name.

Closes #4267

The home feed's cards in src/web/studio/feed.ts no longer emit any .fcard-* class. The type check, bun scripts/design-lint.ts and the design-lint, home-walk, feed-page, home-feed and studio tests pass, as does the new test. I did not run the full suite; the forge runs it on this push.

Each part now uses the §5 component that fits:

• Who: a plain <strong> in the card's head, next to avatar, nameMark and the kind badge.
• Text: a <p class="break">, so long unbroken text still wraps.
• Why: <p class="small muted break">.
• Reply: <p class="small break" data-placement>, with its #N links unchanged.
• Thought text: <p class="break"> with each line escaped and a <br /> between lines. .fcard-text used to keep line breaks with white-space: pre-wrap, so runs of spaces are no longer preserved.
• Reply and decide forms: <form class="stack"> with .input on the textarea. The submit btn sits in a .bar so it keeps the 44px touch height. The forms post the same fields to the same actions, and the textarea keeps maxlength="2000".
• Dismiss and mute: unchanged.

Not done:

• Not touched: the stylesheet rules and docs/DESIGN.md, as asked. Part two removes them.
• field() not used: it drops maxlength on a textarea and adds a visible label, so the textarea is a bare .input instead.
• row() not used: it is an <li>, which doesn't fit inside a card.
• flow_card.ts untouched: it still uses fcard-reason and fcard-unblock. It is outside this issue's file list.

Tests:

• New test/feed-card-markup.test.ts asserts no fcard- appears in a post or a thought. It also checks the words, links, forms, escaping and line breaks are still there.
• I changed test/home-walk.test.ts, whose assertion matched fcard-who">scribe</strong; it now matches <strong>scribe</strong. That test was tied to the old class name.