Preserve /people view toggle on back navigation

[rynaco]

Changes

Fixes a small UX issue on the /people page. I'm applying for the Technical CSM role and this will really speed up my research about the team ;)

Before: From the People page, switching to the Map view, clicking a team member's profile, and then hitting the browser back button drops you back on the List view — losing the user's place.

After: The active view is persisted in the URL as ?view=map, so browser back-navigation restores the view the user came from.

Considered persisting the user's pan/zoom position on the map (so back-navigation returns them to the exact spot they were looking at, not just the default view). Decided against bundling it into this PR as the implementation adds more complexity (would need moveend listeners writing to sessionStorage or extra URL params for lng/lat/zoom), and just returning to the map view (instead of resetting to list) is already a meaningful improvement by itself.

Implementation

• Read the view query param on mount (and on any location.search change, so browser back/forward stays in sync) and reflect it in the existing activeTab state.
• On toggle change, update the URL with navigate(..., { replace: true }) so toggling doesn't pollute history — only navigating away from /people creates a back-stop.
• ?view=list is omitted from the URL (it's the default), keeping URLs clean.
• Other query params are preserved via URLSearchParams.set/delete rather than string replacement.

Uses the same useLocation from @reach/router + gatsby navigate pattern already used in src/components/Editor/index.tsx, TemplatesLibrary/index.tsx, and IntegrationsLibrary/index.tsx.

Checklist

• I've read the docs and/or content style guides. (n/a — code change)
• Words are spelled using American English (n/a — code change)
• Use relative URLs for internal links (n/a — code change)
• I've checked the pages added or changed in the Vercel preview build (will check once preview is ready)
• If I moved a page, I added a redirect in vercel.json (n/a — no page moved)

Verification

Verified locally with pnpm start:

1. /people → List view, URL is clean
2. Click Map → URL becomes /people?view=map, view switches to map
3. Click a team member → opens /community/profiles/<id>
4. Browser back → returns to /people?view=map with map view active ✓
5. Direct load of /people?view=map opens in map view; direct load of /people opens in list view
6. Toggling List ↔ Map repeatedly does not add browser history entries (uses replace: true)