feat(ui): time-window selector for the analytics dashboard

[JSONbored]

Add a 7d/30d/90d window toggle to the analytics dashboard header that re-parameterizes the maintainer-dashboard fetch (the endpoint already accepts a days param). One control that drives the existing useApiResource query key.

Deliverables

• Window toggle (ToggleGroup from components/ui/toggle-group.tsx) in app.analytics.tsx header
• Thread the selected window into the useApiResource fetch/query key (lib/api/use-api-resource.ts)
• Persist the choice via use-local-storage (apps/gittensory-ui/src/lib/use-local-storage.ts)
• Vitest test: default window, switching windows re-keys the fetch, persisted value restores (both branches of the persisted-vs-default read)

References

• apps/gittensory-ui/src/routes/app.analytics.tsx
• apps/gittensory-ui/src/lib/api/use-api-resource.ts
• apps/gittensory-ui/src/lib/use-local-storage.ts
• apps/gittensory-ui/src/components/ui/toggle-group.tsx

Part of #1967.

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📸 Required: before/after screenshots (this is a UI change)

Non-negotiable. PRs that change UI must include a before/after screenshot table. PRs without it are automatically closed — no exceptions.

Rules:

• Show every page/feature you changed — before and after, one row each.
• Use the markdown table below. Screenshots go inside the table only — no large full-size images pasted elsewhere in the PR.
• Each cell is a clickable thumbnail (a small image linking to the full-size image) with a one-line caption underneath.
• Upload screenshots to the PR by drag-and-drop (GitHub hosts them on its CDN). Do NOT commit image files to the repo.

Copy this and fill it in (replace FULL_IMAGE_URL with the URL GitHub gives you after you drop the image in):

| Page / Feature | Before | After |
|---|---|---|
| `/your-route` | [<img src="FULL_IMAGE_URL" width="260">](FULL_IMAGE_URL)<br><sub>before: short caption</sub> | [<img src="FULL_IMAGE_URL" width="260">](FULL_IMAGE_URL)<br><sub>after: short caption</sub> |

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size: S · held for later release (gittensor:feature once activated)

[linear-code]

JSO-2300