Consolidate OpenAI server: unify implementations, add multi-protocol support

.github/build.sh

@@ -6,5 +6,53 @@
 # SPDX-License-Identifier: MIT
 
 mkdir -p build
-cmake -Bbuild $@ || exit 1
-cmake --build build --config Release -j$(nproc) || exit 1
+
+# Build parallelism. Defaults to all cores; RAM-limited CI runners (notably GitHub's
+# ~7 GB macOS arm64) export BUILD_JOBS lower (e.g. 2) so the large httplib.cpp + the 134
+# llama.cpp model TUs do not exhaust memory and get the runner OOM-killed mid-compile
+# (which surfaces as a SIGTERM / "runner received a shutdown signal", not a clean timeout).
+JOBS="${BUILD_JOBS:-}"
+if [ -z "$JOBS" ]; then
+  JOBS="$( { command -v nproc >/dev/null 2>&1 && nproc; } || sysctl -n hw.ncpu 2>/dev/null || echo 4 )"
+fi
+
+# Fetch sccache when caching is requested but the runner/container doesn't ship it — the
+# dockcross cross-compile containers (manylinux/Android) and Linux hosts have no sccache,
+# while macOS installs it via brew in the workflow. Best-effort and inert-safe: any failure
+# leaves sccache absent, so the build just proceeds uncached. The static musl binary runs in
+# any x86_64 Linux container (the cross-compile host is always x86_64).
+if [ "${USE_CACHE:-true}" = "true" ] && [ -n "${SCCACHE_WEBDAV_TOKEN:-}${SCCACHE_GHA_ENABLED:-}" ] \
+   && ! command -v sccache >/dev/null 2>&1 \
+   && [ "$(uname -s)" = "Linux" ] && [ "$(uname -m)" = "x86_64" ]; then
+  SCCACHE_REL="sccache-v0.8.2-x86_64-unknown-linux-musl"
+  echo "build.sh: fetching ${SCCACHE_REL} (no sccache on PATH)..."
+  if curl -fsSL --proto =https --proto-redir =https \
+        "https://github.com/mozilla/sccache/releases/download/v0.8.2/${SCCACHE_REL}.tar.gz" \
+        -o /tmp/sccache.tgz && tar -xzf /tmp/sccache.tgz -C /tmp; then
+    export PATH="/tmp/${SCCACHE_REL}:$PATH"
+    echo "build.sh: sccache -> $(command -v sccache || echo 'still missing')"
+  else
+    echo "build.sh: sccache fetch failed; continuing without cache"
+  fi
+fi
+
+# Optional shared compiler cache: sccache fronting Depot Cache (WebDAV). Enabled only when
+# USE_CACHE is true AND sccache + a cache token are present, so it stays inert before the
+# DEPOT_TOKEN secret is configured and on fork PRs (secrets hidden) — those just compile
+# normally. sccache is content-addressed, so a cache hit is bit-identical to a fresh -O3
+# compile (release-safe), and it degrades to direct compilation if the cache is unreachable.
+LAUNCH=""
+if [ "${USE_CACHE:-true}" = "true" ] && command -v sccache >/dev/null 2>&1 \
+   && [ -n "${SCCACHE_WEBDAV_TOKEN:-}${SCCACHE_GHA_ENABLED:-}" ]; then
+  LAUNCH="-DCMAKE_C_COMPILER_LAUNCHER=sccache -DCMAKE_CXX_COMPILER_LAUNCHER=sccache"
+  echo "build.sh: sccache ON (endpoint=${SCCACHE_WEBDAV_ENDPOINT:-default}), building with -j${JOBS}"
+else
+  echo "build.sh: sccache OFF, building with -j${JOBS}"
+fi
+
+cmake -Bbuild $LAUNCH $@ || exit 1
+cmake --build build --config Release -j"${JOBS}" || exit 1
+
+if command -v sccache >/dev/null 2>&1; then
+  sccache --show-stats || true
+fi