fix: yaml syntax

The workflow-level env set RUSTC_WRAPPER=sccache for every step,
including the install step itself. cargo install sccache then
tried to invoke `sccache rustc -vV` to detect the toolchain before
sccache existed on PATH, failing with "No such file or directory".
Override RUSTC_WRAPPER to empty on the install step so cargo uses
rustc directly; subsequent steps still inherit the wrapper.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

.gitea/workflows/ci.yml

@@ -2,11 +2,20 @@ name: CI
 
 on:
   push:
-    branches: ['**']
-    tags: ['v*']
+    branches: ["**"]
+    tags: ["v*"]
   pull_request:
     branches: [main]
 
+env:
+  RUSTC_WRAPPER: sccache
+  SCCACHE_BUCKET: sccache
+  SCCACHE_ENDPOINT: http://caveman.kosherinata.internal:9000
+  SCCACHE_REGION: auto
+  SCCACHE_S3_USE_SSL: "false"
+  AWS_ACCESS_KEY_ID: ${{ secrets.SCCACHE_S3_ACCESS_KEY }}
+  AWS_SECRET_ACCESS_KEY: ${{ secrets.SCCACHE_S3_SECRET_KEY }}
+
 jobs:
   check:
     name: Format, lint, build, test
@@ -14,6 +23,16 @@ jobs:
     steps:
       - uses: actions/checkout@v4
 
+      - name: Ensure sccache with S3 support
+        env:
+          RUSTC_WRAPPER: ""
+        run: |
+          if sccache --version 2>/dev/null && sccache --show-stats 2>/dev/null; then
+            echo "sccache with S3 support already installed"
+          else
+            cargo install sccache --features s3 --locked
+          fi
+
       - name: Check formatting
         run: cargo fmt --check --all
 
@@ -26,6 +45,9 @@ jobs:
       - name: Test
         run: cargo test --workspace
 
+      - name: Show sccache stats
+        run: sccache --show-stats
+
   srpm-cortex:
     name: Build cortex SRPM
     runs-on: fedora
@@ -76,7 +98,7 @@ jobs:
         uses: actions/upload-artifact@v3
         with:
           name: srpm-cortex
-          path: '*.src.rpm'
+          path: "*.src.rpm"
 
   srpm-neuron:
     name: Build neuron SRPM
@@ -128,7 +150,7 @@ jobs:
         uses: actions/upload-artifact@v3
         with:
           name: srpm-neuron
-          path: '*.src.rpm'
+          path: "*.src.rpm"
 
   copr-cortex:
     name: Publish cortex to COPR