ci(contracts): remove the serial coverage baseline job

It was a one-off benchmark (CI serial 14m9s vs the sharded matrix ~7m21s). Keeping it made
it the workflow's long pole on every PR, so drop it now that the number is captured; the
sharded matrix plus merge remains the coverage gate.

Signed-off-by: Miguel_LZPF <miguel.carpena@io.builders>

Author: MiguelLZPF

.github/workflows/100-flow-ats-test.yaml

@@ -202,58 +202,3 @@ jobs:
           token: ${{ secrets.CODECOV_TOKEN }}
           files: packages/ats/contracts/coverage/lcov.info
           disable_search: true
-
-  # Serial baseline: run the FULL coverage suite on a single runner (SHARD_TOTAL=1) — the one-shot
-  # run that the sharded `coverage-ats` matrix parallelises. It does NOT upload to Codecov (the
-  # merge-coverage job owns that), and runs independently of the matrix. Kept as the wall-clock
-  # reference and a ground-truth that the sharded+merged report matches a single run; its lcov is
-  # published as an artifact for that comparison.
-  coverage-serial:
-    name: coverage (serial baseline)
-    runs-on: token-studio-linux-large
-    timeout-minutes: 45
-    env:
-      CONTRACT_SIZER_RUN_ON_COMPILE: "false"
-      REPORT_GAS: "false"
-
-    steps:
-      - name: Harden Runner
-        uses: step-security/harden-runner@58077d3c7e43986b6b15fba718e8ea69e387dfcc # v2.15.1
-        with:
-          egress-policy: audit
-
-      - name: Checkout repository
-        uses: actions/checkout@08c6903cd8c0fde910a37f88322edcfb5dd907a8 # v5.0.0
-
-      - name: Setup NodeJS Environment
-        uses: actions/setup-node@49933ea5288caeca8642d1e84afbd3f7d6820020 # v4.4.0
-        with:
-          node-version-file: .nvmrc
-          cache: "npm"
-
-      - name: Restore dependencies from cache
-        id: deps-cache
-        uses: actions/cache@5a3ec84eff668545956fd18022155c47e93e2684 # v4.2.3
-        with:
-          path: |
-            node_modules
-            */*/node_modules
-            */*/*/node_modules
-            ~/.npm
-          key: ${{ runner.os }}-deps-${{ hashFiles('package-lock.json') }}
-
-      - name: Install dependencies
-        if: steps.deps-cache.outputs.cache-hit != 'true'
-        run: npm ci --ignore-scripts
-
-      - name: Run full coverage (serial, single run)
-        run: npm run test:coverage --workspace=packages/ats/contracts
-
-      - name: Upload serial coverage artifact
-        if: ${{ !cancelled() }}
-        uses: actions/upload-artifact@b7c566a772e6b6bfb58ed0dc250532a479d7789f # v6.0.0
-        with:
-          name: coverage-serial
-          path: packages/ats/contracts/coverage/lcov.info
-          if-no-files-found: error
-          retention-days: 1