Fix test workflows to use build artifacts instead of local binary

- Build workflow now uploads ollama binary as artifact with 7-day retention
- Test workflows download artifact instead of expecting local binary
- Eliminates 'ollama binary not found' error when running tests
- Enables build-once, test-multiple-times workflow pattern
- Added binary verification step to confirm artifact download

.github/workflows/tesla-k80-ci.yml

@@ -37,3 +37,15 @@ jobs:
       - name: Build Go binary
         run: |
           go build -v -o ollama .
+
+      - name: Verify binary was created
+        run: |
+          ls -lh ollama
+          ./ollama --version
+
+      - name: Upload ollama binary as artifact
+        uses: actions/upload-artifact@v4
+        with:
+          name: ollama-binary
+          path: ollama
+          retention-days: 7