Describe how Fit fills the tile tab and fits again on resize

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

Development.md

@@ -14,7 +14,7 @@ npm run build        # writes dist/ and regenerates index.html
 ./build.sh           # the same under `set -o pipefail`, for callers that pipe the output
 php tools/make-user.php <name> <password> [admin|user]        # an account; every tool signs in (see Accounts)
 php tests/php/accounts.test.php                               # the API's account rules, no server needed (CI's gate job)
-node tools/seed-e2e.mjs && node tools/e2e.mjs                 # 1382 editor checks, screenshots in /tmp/gm-e2e-*.png
+node tools/seed-e2e.mjs && node tools/e2e.mjs                 # 1384 editor checks, screenshots in /tmp/gm-e2e-*.png
 GM_STEPS=20 node tools/e2e.mjs                                # or 1-12, or 6,20 — a subset while working on one step
 ./e2e.sh start [GM_STEPS]                                     # the same run detached, see below
 ./e2e.sh status                                               # live progress, or the last run's result

Tiles.md

@@ -127,6 +127,8 @@ Kind, rate, playback, the solid switch, the collision scale and the sort offset
 - For a plain tile the grid is the one tile and the sample map shows it repeated. Both run the
   animation at the set rate.
 - A drag pans the board, the wheel zooms it; nothing on it is edited.
+- **Fit** fills the tab with the board, up to 600 %, so small tiles are shown large. Until you pan
+  or zoom by hand, the board fits itself again when the tab is resized or the tiles change size.
 - The **picture list** on the right is the animation: **+ Picture** adds a texture or a frame,
   **Remove** takes the selected one out, and dragging a row to another place reorders the steps.
   Every one of those is an undo step.