feat(galerias): upload several images at once, clear errors and JPEG XL placeholders

CLAUDE.md

@@ -89,7 +89,7 @@ An unpublished gym 404s publicly but previews for staff.
 - YourFit modalidades use their brand glyphs: `fitme-yourfit-*.svg` were traced (2026-10-26) from the left tile of the wordmarks `uploads/modalidades/icons/yourfit-*.png` (150×33, the only source found) into one even-odd `currentColor` path, so they keep the CSS colour/hover and the transform animations (no stroke draw).
 
 ## Imagens / JPEG XL (2026-10-26)
-Fleet transition to JPEG XL (root `Y:\GitTea\CLAUDE.md`, "Images"); fitme3070 is the reference site. Uploads already accept `.jxl` (gyms header/logo, gallery photos).
+Fleet transition to JPEG XL (root `Y:\GitTea\CLAUDE.md`, "Images"); fitme3070 is the reference site. Uploads already accept `.jxl` (gyms header/logo, gallery photos). The gallery edit page (`views/admin/galerias/edit.php`) takes several files at once (`images[]`, one flash with the count plus each refused file and why, from `db_gallery_image_upload(..., &$error)`; limits shown from `gallery_upload_max_bytes()` / `max_file_uploads` / `post_max_size`, and a POST over `post_max_size` gets its own message). A `.jxl` without fallback shows as a «JPEG XL» placeholder tile with its filename (Chrome can't draw it); with a fallback it uses `img_tag()`.
 - **Optimizer** (`config/functions_images.php`, built 2026-10-26): `img_optimize()` hands `.jxl` to `img_jxl_optimize()`, which decodes with `djxl` (or Imagick if it lists JXL), resizes with GD, re-encodes a smaller `.jxl` with `cjxl -d 1.0` when resized, and always writes the fallback **`foto.jxl.webp`** (`.jxl.jpg` if GD has no WebP) beside it. Idempotent (skips when the fallback is newer and within the cap). With no decoder it returns `skipped` («JPEG XL sem descodificador no servidor»), uploads never fail.
 - **No decoder exists yet** (checked 2026-10-26): the VPS `fitme` image (php:8.4-apache, Debian trixie) has GD only; the dev `webdevops/php-apache:8.2` has Imagick without JXL. Both need `libjxl-tools` (cjxl/djxl) installed. 2026-10-26: added to the VPS `/srv/stacks/fitme.andmore.pt/Dockerfile` apt line (backup `Dockerfile.bak-20261026`), active only after `docker compose build && docker compose up -d` there (the user runs it); on dev it is installed by hand in the running container (`apt-get install libjxl-tools` as root) and is lost when the TrueNAS app recreates it. Until then `.jxl` uploads have no fallback and show only in browsers with JXL (Safari). After installing, press «Otimizar» on each gallery to backfill.
 - **Serving:** `img_tag($rel, $attrs)` (`<picture><source type="image/jxl"><img src=fallback>`, plain `<img>` otherwise), `img_css_bg($rel)` (hero: `url(fallback)` then `image-set()` with the JXL), `img_compat_rel()` (single-URL places: lightbox link, JSON-LD image, admin preview), `img_list_dir()` (gallery listings, hides `*.jxl.*`). Used in `site/includes/gallery.php` (lightbox shows the tile's `currentSrc`), `site/index.php` hero, `include.php` preload (`type="image/jxl"` for a JXL hero), `seo.php`, navbar logos. `picture { display: contents }` in `style.css` keeps the old img sizing.