ci: move lint back to hosted runners, arc image has no make/gcc

Follow-up to 42541dd4f, which routed lint to arc-runner-set. Both of its
jobs failed there in one second (run 30637392862): the runner image has
git, curl, unzip, tar, ldd and python3, but not make, and build-scripts
additionally needs gcc because the packaging-script tests compile a
throwaway binary and inspect it with ldd.

golangci-lint needs make twice over: `make protogen-go` (which also wants
curl + unzip to fetch protoc) and `make lint` itself. So both jobs go back
to ubuntu-latest.

gh-pages.yml stays on arc-runner-set and is unaffected: it uses no make and
no C toolchain, and setup-go / actions-hugo fetch their own toolchains.

The preflight steps stay. They cost about a second on the hosted pool, and
they are what turned this into a one-second named failure instead of an
opaque one midway through a build. When the runner image gains make + gcc,
re-routing is one runs-on line per job. Any such re-route must stay
push-only: lint also runs on pull_request, and fork PRs execute untrusted
code that must not reach a persistent self-hosted runner.

Signed-off-by: Ettore Di Giacinto <mudler@localai.io>
Assisted-by: Claude Code:claude-opus-5 [ClaudeCode]

.github/workflows/lint.yml

@@ -33,7 +33,12 @@ jobs:
     # straight minutes on 2026-07-31 while arc-runner-set kept completing jobs.
     # Lint is small and runs on every commit, so it is a good candidate to move
     # off the contended pool.
-    runs-on: ${{ (github.event_name == 'push' && github.repository == 'mudler/LocalAI') && 'arc-runner-set' || 'ubuntu-latest' }}
+    # REVERTED to hosted: the arc-runner-set image has git, curl, unzip, tar,
+    # ldd and python3, but NOT make (nor gcc). Measured on run 30637392862,
+    # where the preflight below named both. Re-route here once the runner image
+    # ships a C toolchain and make; the preflight stays so the next attempt
+    # fails by name in one second instead of opaquely mid-build.
+    runs-on: ubuntu-latest
     steps:
       - name: Preflight - required host tools
         # The hosted images ship these; a self-hosted container image may not.
@@ -86,7 +91,12 @@ jobs:
     #
     # Push-only self-hosted routing, same fork-safety reasoning as
     # golangci-lint above.
-    runs-on: ${{ (github.event_name == 'push' && github.repository == 'mudler/LocalAI') && 'arc-runner-set' || 'ubuntu-latest' }}
+    # REVERTED to hosted: the arc-runner-set image has git, curl, unzip, tar,
+    # ldd and python3, but NOT make (nor gcc). Measured on run 30637392862,
+    # where the preflight below named both. Re-route here once the runner image
+    # ships a C toolchain and make; the preflight stays so the next attempt
+    # fails by name in one second instead of opaquely mid-build.
+    runs-on: ubuntu-latest
     steps:
       - name: Preflight - required host tools
         # This job additionally needs a C toolchain: the packaging-script tests