fix(ci): disable sccache on the dockcross/Linux-host builds (sccache crashed in-container)

The phase-2 cross-compile caching broke the dockcross builds: inside the manylinux
container the fetched sccache panicked while wrapping the cross-compiler (log: a Rust
backtrace + "Run with SCCACHE_LOG=debug", failing ggml.c.o), and because sccache is the
compiler launcher that fails the whole build. The build.sh "inert-safe" guard only covers
sccache being *absent*, not present-but-crashing.

Remove the sccache env from the 4 dockcross jobs (manylinux_2_28 CUDA, manylinux2014,
Linux aarch64, Android aarch64) and the Linux-host C++ test job. With no token reaching
those jobs, build.sh skips the fetch and they compile normally (uncached, green) again.

macOS caching (phase 1) is unaffected and stays — it uses native clang + brew sccache and
is proven working/fast. The build.sh fetch logic remains but is dormant without a token.

Dockcross caching is deferred: it needs an sccache-in-container health check (probe-compile
before trusting the launcher) and SCCACHE_LOG=debug diagnosis of the cross-compiler panic.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01JdLpWD8nedY7LwNnHefZLF

Author: claude

.github/workflows/publish.yml

@@ -171,11 +171,6 @@ jobs:
     name: Cross-Compile manylinux_2_28 x86_64 (CUDA)
     needs: [startgate, build-webui]
     runs-on: ubuntu-latest
-    env:
-      USE_CACHE: ${{ github.event_name != 'workflow_dispatch' || inputs.use_cache }}
-      SCCACHE_WEBDAV_ENDPOINT: https://cache.depot.dev
-      SCCACHE_WEBDAV_TOKEN: ${{ secrets.DEPOT_TOKEN }}
-      DOCKCROSS_ARGS: "-e SCCACHE_WEBDAV_ENDPOINT -e SCCACHE_WEBDAV_TOKEN -e USE_CACHE"
     steps:
       - uses: actions/checkout@v6
       - name: Download shared WebUI assets
@@ -205,11 +200,6 @@ jobs:
     name: Cross-Compile manylinux2014 x86_64
     needs: [startgate, build-webui]
     runs-on: ubuntu-latest
-    env:
-      USE_CACHE: ${{ github.event_name != 'workflow_dispatch' || inputs.use_cache }}
-      SCCACHE_WEBDAV_ENDPOINT: https://cache.depot.dev
-      SCCACHE_WEBDAV_TOKEN: ${{ secrets.DEPOT_TOKEN }}
-      DOCKCROSS_ARGS: "-e SCCACHE_WEBDAV_ENDPOINT -e SCCACHE_WEBDAV_TOKEN -e USE_CACHE"
     steps:
       - uses: actions/checkout@v6
       - name: Download shared WebUI assets
@@ -239,11 +229,6 @@ jobs:
     name: Cross-Compile Linux aarch64 (LTS)
     needs: [startgate, build-webui]
     runs-on: ubuntu-latest
-    env:
-      USE_CACHE: ${{ github.event_name != 'workflow_dispatch' || inputs.use_cache }}
-      SCCACHE_WEBDAV_ENDPOINT: https://cache.depot.dev
-      SCCACHE_WEBDAV_TOKEN: ${{ secrets.DEPOT_TOKEN }}
-      DOCKCROSS_ARGS: "-e SCCACHE_WEBDAV_ENDPOINT -e SCCACHE_WEBDAV_TOKEN -e USE_CACHE"
     steps:
       - uses: actions/checkout@v6
       - name: Download shared WebUI assets
@@ -273,11 +258,6 @@ jobs:
     name: Cross-Compile Android aarch64
     needs: [startgate, build-webui]
     runs-on: ubuntu-latest
-    env:
-      USE_CACHE: ${{ github.event_name != 'workflow_dispatch' || inputs.use_cache }}
-      SCCACHE_WEBDAV_ENDPOINT: https://cache.depot.dev
-      SCCACHE_WEBDAV_TOKEN: ${{ secrets.DEPOT_TOKEN }}
-      DOCKCROSS_ARGS: "-e SCCACHE_WEBDAV_ENDPOINT -e SCCACHE_WEBDAV_TOKEN -e USE_CACHE"
     steps:
       - uses: actions/checkout@v6
       - name: Download shared WebUI assets
@@ -494,10 +474,6 @@ jobs:
     name: C++ Tests Ubuntu Latest x86_64
     needs: startgate
     runs-on: ubuntu-latest
-    env:
-      USE_CACHE: ${{ github.event_name != 'workflow_dispatch' || inputs.use_cache }}
-      SCCACHE_WEBDAV_ENDPOINT: https://cache.depot.dev
-      SCCACHE_WEBDAV_TOKEN: ${{ secrets.DEPOT_TOKEN }}
     steps:
       - uses: actions/checkout@v6
       - uses: actions/setup-java@v5