fix: address review findings in the v2 stack fix PR

Board scaling: no sideways scrolling
- Revert the pannable narrow canvas. The canvas fits the viewport again and
  `.viewport` goes back to `overflow: clip`, so a board can never widen the
  document or scroll horizontally.
- Fix the unreadable-narrow-board regression at the real cause instead: cap the
  inverse UI compensation at 2x (50% canvas scale). Down to 50% text and
  controls keep their physical size; below it the board zooms out as a whole, so
  a 200x200 logical tile hosts at most 28px logical text rather than 96px and
  content stops overlapping its neighbours.

Touch editing
- Add `touch-action: none` to `.board-grid-entry`, the dnd-kit draggable and its
  own drag handle. The 200ms touch activation delay is useless if the browser
  has already handed the gesture to page panning and emitted `pointercancel`.
  Only edit mode renders this element.

Custom widgets
- Memoize the merged `data`/`status`/`options` passed to `CustomJsxRenderer`.
  They were rebuilt every render, so the compiled-template memo never hit and
  the new reference-identity boundary key changed on every render, resetting the
  error boundary and forcing an extra reconciliation of the widget subtree.
- Keep the cache key when the shared Redis cache is unavailable so the
  process-local cache still absorbs polling instead of sending every widget
  refresh upstream.
- Reclaim the shared cache's LRU/size/byte bookkeeping for TTL-expired entries
  and touch the LRU in the same script, so expired ghosts stop consuming the
  64 MiB budget and a read costs one round trip instead of two.

Forwarded IP
- Restore `ipAddressFromHeaders` to the full forwarding chain and add
  `trustedIpAddressFromHeaders` for the last hop. Repointing the shared helper
  had collapsed MCP failed-auth rate limiting into a single bucket for every
  client behind a reverse proxy and replaced the client IP with the proxy IP in
  API-key auth logs.

Runtime and restore
- Make the new /appdata ownership migration best-effort. Under `set -e` a mount
  that rejects chown (CIFS/SMB, fixed-uid NFS) turned into a container that
  refuses to start, and /appdata was never chowned before.
- Report malformed metadata.json as such instead of blaming the archive.

apps/docs/docs/getting-started/after-the-installation.mdx

@@ -213,9 +213,11 @@ otherwise the collision chain reflows neighboring tiles automatically.
 Every `1 × 1` tile has a logical content size of `200 × 200` pixels.
 Larger tiles use multiples of that fixed unit, with a consistent gap between cells.
 Homarr scales the complete board uniformly, like zooming a page.
-Below 100%, Homarr preserves the widget's readable typography and control density instead of shrinking each widget
-independently. Scaling stops at 50%; if the selected layout is still wider than the viewport, the board scrolls
-horizontally instead of making tiles and controls unusably small.
+The complete canvas always fits the available width without horizontal board scrolling.
+Down to 50%, Homarr preserves the widget's readable typography and control density instead of shrinking each widget
+independently. Below 50% it stops compensating and scales text and controls together with the board, like zooming out a
+page, so tile content keeps its designed proportions instead of overlapping neighboring tiles. Add a narrow responsive
+layout — Homarr already creates and reflows the protected Mobile layout — when a board has to stay readable on small screens.
 It does not squeeze or reflow the content of individual widgets, so a widget keeps the same design and proportions across screen sizes.
 
 On a narrow screen, Homarr uses the **Mobile layout** for the selected board and stacks the board content vertically while