feat: helpers and actions

Author: deluca-mike

.github/CODEOWNERS

@@ -0,0 +1,3 @@
+# Global rule:
+*     @xmtp/backend
+*.md  @xmtp/documentation

.github/workflows/coverage.yml

@@ -0,0 +1,41 @@
+name: Forge Coverage
+
+on:
+  push:
+    branches:
+      - main
+  pull_request:
+
+permissions: write-all
+
+jobs:
+  check:
+    name: Code Coverage
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          submodules: recursive
+
+      - name: Install Foundry
+        uses: foundry-rs/foundry-toolchain@v1
+
+      - name: Install lcov
+        uses: hrishikesh-kadam/setup-lcov@v1
+
+      - name: Run coverage
+        id: coverage
+        env:
+          MNEMONIC: ${{ secrets.MNEMONIC_FOR_TESTS }}
+          MAINNET_RPC_URL: ${{ secrets.MAINNET_RPC_URL }}
+          ETHERSCAN_API_KEY: ${{ secrets.ETHERSCAN_API_KEY }}
+        run: forge coverage --no-match-coverage "(script|test)" --gas-limit 2000000000 --report lcov && lcov --extract lcov.info --rc lcov_branch_coverage=1 --rc derive_function_end_line=0 -o lcov.info 'src/*' && genhtml lcov.info --rc branch_coverage=1 --rc derive_function_end_line=0 -o coverage
+
+      - name: Report code coverage
+        uses: zgosalvez/github-actions-report-lcov@v3
+        with:
+          coverage-files: lcov.info
+          artifact-name: code-coverage-report
+          minimum-coverage: 95
+          github-token: ${{ secrets.GITHUB_TOKEN }}
+          update-comment: true

.github/workflows/gas.yml

@@ -0,0 +1,42 @@
+name: Forge Tests Gas Report
+
+on:
+  push:
+    branches:
+      - main
+  pull_request:
+
+permissions: write-all
+
+jobs:
+  check:
+    name: Gas report
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          submodules: recursive
+
+      - name: Install Foundry
+        uses: foundry-rs/foundry-toolchain@v1
+
+      - name: Run Forge tests with gas report
+        env:
+          # make fuzzing semi-deterministic to avoid noisy gas cost estimation
+          # due to non-deterministic fuzzing (but still use pseudo-random fuzzing seeds)
+          FOUNDRY_FUZZ_SEED: 0x${{ github.event.pull_request.base.sha || github.sha }}
+          MAINNET_RPC_URL: ${{ secrets.MAINNET_RPC_URL }}
+          ETHERSCAN_API_KEY: ${{ secrets.ETHERSCAN_API_KEY }}
+        run: forge test --gas-report --gas-limit 2000000000 > gasreport.ansi
+
+      - name: Compare gas reports
+        uses: Rubilmax/foundry-gas-diff@v3.16
+        id: gas_diff
+
+      - name: Add gas diff to sticky comment
+        if: github.event_name == 'pull_request' || github.event_name == 'pull_request_target'
+        uses: marocchino/sticky-pull-request-comment@v2
+        with:
+          # delete the comment in case changes no longer impact gas costs
+          delete: ${{ !steps.gas_diff.outputs.markdown }}
+          message: ${{ steps.gas_diff.outputs.markdown }}