Improve follow-up environment story coverage

[brsbl]

What was wrong

The follow-up composer story catalog defaulted every Row without an explicit environment fixture to the same local-direct summary, so most functional states repeated one environment treatment. The focused environment matrix covered only direct local/remote and managed local/remote worktrees; it omitted unmanaged, named, and detached worktree shapes, and the detached fixture omitted its machine label so its worktree icon could not render.

What changed

• Rotates the functional overview through a balanced mix of local/remote and direct/worktree summaries instead of relying on the local default.
• Expands Environment matrix with unmanaged, named, and detached worktree rows.
• Supplies the detached fixture's machine label so the production FolderGit environment icon is visible.
• Keeps provisioning on the production Loading spinner because discovery has not yet confirmed the eventual workspace type.
• Changes only Ladle fixtures; there are no product, daemon-wire, SDK, API, CLI, or persistence changes.

Before — parent PR head 7b7f9c645bf88916298e664c444110df18cd2ff3

The matrix stopped after managed local/remote worktrees, and generic overview rows overwhelmingly inherited the local-direct fixture.

After — child head 3c86463a7650be23c225f191194cf39de1f967a8

The matrix exposes every meaningful label/icon shape, while the overview exercises a balanced direct/worktree mix.

How you verified

• Verified live registration from Ladle's /meta.json: thread--timeline--rows--tool--native-skill-call and promptbox--follow-up-prompt-box--environment-matrix both exist.
• Chrome for Testing 152.0.7977.64 rendered both exact routes without a missing-story state or runtime exception. The native-skill story rendered Loaded skill · visual-qa-loop with the Zap icon.
• The exact child-head environment matrix rendered eight composers: provisioning uses Loading; direct local/remote use Laptop; managed, unmanaged, named, and detached worktrees use FolderGit; destroyed uses the archived banner. Every environment-type accessible label matched its fixture.
• The exact child-head overview rendered 21 composers with 9 Laptop, 11 FolderGit, and 1 Loading environment treatments, with no horizontal overflow at 1440×1100.
• pnpm exec turbo run typecheck --filter=@bb/app passed on the final head.
• pnpm exec turbo run lint --filter=@bb/app completed with 0 errors; the repository's existing warnings remain.
• Targeted oxfmt --check and git diff --check passed.
• Safari is not required for this non-marketing Ladle change.

BB-Thread-ID: thr_sjdd7gudiq

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