ci : apply ccache-clear with older/min/dry-run to all ccache jobs (#27602)

* ci : apply ccache-clear with older/min/dry-run to all ccache jobs

Assisted-by: llama.cpp:DeepSeek-v4-Flash-0731

* ci : install gh in ccache-clear if missing (container jobs)

The ccache-clear action relies on the gh CLI, which is not present in
container-based jobs. Install it on demand so those jobs can clear caches.

Assisted-by: llama.cpp:DeepSeek-v4-Flash-0731

* ci : install gh via apt repo in ccache-clear

The install.sh script used previously is no longer served (404). Switch to
the official GitHub CLI apt repository, which is still available.

Assisted-by: llama.cpp:DeepSeek-v4-Flash-0731

* ci : pass --repo to gh cache commands in ccache-clear

In container jobs gh cannot auto-detect the repository from git, so
gh cache list/delete fail with 'failed to run git: not a git repository'.
Pass the repository explicitly via --repo using GITHUB_REPOSITORY.

Assisted-by: llama.cpp:DeepSeek-v4-Flash-0731

* ci : drop -new suffix from vulkan ccache key

The -new suffix was only needed to force a fresh cache. With
ccache-clear now evicting stale caches, the original key can be used
again. The old ccache-vulkan-ubuntu-24.04-arm-new entries still match
the ccache-clear key prefix and are cleaned up automatically.

Assisted-by: llama.cpp:DeepSeek-v4-Flash-0731

* ci : fix ccache-clear date parsing on macOS (BSD date)

macOS ships BSD date, which has no -d option. The older cutoff check
was silently disabled there: 'date: illegal option -- d' errors in the
log and the loop was only stopped by the min limit, risking deletion
of caches not older than the cutoff (e.g. saved by a concurrent job).

Parse the ISO-8601 timestamps with GNU date when available and fall
back to BSD date otherwise (TZ=UTC, fractional seconds dropped).

Assisted-by: llama.cpp:DeepSeek-v4-Flash-0731

* ci : extract ccache-clear logic into scripts/ccache-clear.sh

The composite action now consists of a dedicated step that installs the
GitHub CLI when missing (e.g. in container jobs) and a thin step that
calls the new script. The script follows the make-release-checks.sh
conventions (usage/env header, set -euo pipefail, CLI flags) and only
checks that gh is available. The action inputs are unchanged, so the
workflow steps are untouched.

Assisted-by: llama.cpp:DeepSeek-v4-Flash-0731

* ci : remove unused apple ccaches

.github/workflows/server.yml

@@ -128,6 +128,16 @@ jobs:
           export LLAMA_ARG_BACKEND_SAMPLING=1
           SLOW_TESTS=1 ./tests.sh
 
+      - name: ccache-clear
+        uses: ./.github/actions/ccache-clear
+        env:
+          GH_TOKEN: ${{ github.token }}
+        with:
+          key: server-ubuntu-24.04-arm
+          older: 5m
+          min: 1
+          dry-run: ${{ github.event_name != 'push' || github.ref != 'refs/heads/master' }}
+
   windows:
     runs-on: windows-2025
 
@@ -181,3 +191,13 @@ jobs:
           cd tools/server/tests
           export SLOW_TESTS="1"
           ./tests.sh
+
+      - name: ccache-clear
+        uses: ./.github/actions/ccache-clear
+        env:
+          GH_TOKEN: ${{ github.token }}
+        with:
+          key: server-windows-2025-x64
+          older: 5m
+          min: 1
+          dry-run: ${{ github.event_name != 'push' || github.ref != 'refs/heads/master' }}