#9 - Build xberg PHP extension alongside kreuzberg in 8.5 image

[nikola-jovanovic-php]

Closes #9

Changes (8.5/Dockerfile only)

• New xberg-builder stage: builds crates/xberg-php from xberg-io/xberg at pinned v1.0.0-rc.28 (no stable tag exists yet — bump XBERG_VERSION when one lands), same shape and retry loop as the previous kreuzberg stage. xberg vendors Tesseract statically (no libtesseract-dev needed), but its heic feature links system libheif ≥ 1.21, so the stage builds libheif 1.23.0 from source (trixie apt ships 1.19.8) — mirroring xberg's own CI.
• Final image: ships xberg.so commented out in conf.d/xberg.ini, copies libheif.so.1 to /usr/local/lib (on LD_LIBRARY_PATH), and adds the codec runtime packages (libde265-0 libaom3 libx265-215 libdav1d7 libnuma1) so the extension is loadable when consumers enable it.
• Kreuzberg removed (per review): the kreuzberg-builder stage and its extension block are deleted — the image ships only xberg. Note this also drops the broken v4.9.8 clone (the old kreuzberg-dev/kreuzberg repo was renamed to xberg-io/xberg, so uncached 8.5 builds were failing on master anyway).

Verification (local arm64 build)

• Full docker build succeeds.
• extension=xberg enabled → php -m lists xberg; class_exists('Xberg\CacheStats') → true.
• ldd xberg.so: zero unresolved libs; libheif.so.1 resolves to the bundled 1.23 copy.
• No kreuzberg artifacts remain (conf.d/kreuzberg.ini, kreuzberg.so gone).

[deluxetom]

lets just keep xberg and remove kreuzberg

[nikola-jovanovic-php]

Removed in ddf68f4 — the kreuzberg-builder stage and the final-stage kreuzberg block are gone; the image now ships only xberg.so (still commented out in php.ini). Verified locally: xberg loads, no kreuzberg artifacts remain.

One note: any downstream image that had extension=kreuzberg enabled will break on its next pull of :8.5. It shipped commented out, so that should be nobody — flagging just in case.