feat: devkit CI workflow, clippy check, benchmark CI, and README benchmark results

Closes #184
Closes #185
Closes #186
Closes #187

Co-Authored-By: NteinPrecious <NteinPrecious@users.noreply.github.com>

Author: NteinPrecious

.github/workflows/devkit-bench.yml

@@ -0,0 +1,30 @@
+name: Devkit Benchmarks
+
+on:
+  pull_request:
+    branches: [main]
+    paths: ['packages/devkit/**']
+
+jobs:
+  benchmark:
+    name: Criterion Benchmarks
+    runs-on: ubuntu-latest
+    defaults:
+      run:
+        working-directory: packages/devkit
+    steps:
+      - uses: actions/checkout@v4
+      - uses: dtolnay/rust-toolchain@stable
+      - uses: Swatinem/rust-cache@v2
+        with:
+          workspaces: packages/devkit
+      - name: Compile benchmarks
+        run: cargo bench --no-run
+      - name: Run benchmarks (quick)
+        run: cargo bench -- --output-format bencher 2>&1 | tee benchmark-output.txt || true
+      - name: Post results to step summary
+        run: |
+          echo "## Devkit Benchmark Results" >> $GITHUB_STEP_SUMMARY
+          echo "\`\`\`" >> $GITHUB_STEP_SUMMARY
+          cat benchmark-output.txt >> $GITHUB_STEP_SUMMARY || echo "No output captured." >> $GITHUB_STEP_SUMMARY
+          echo "\`\`\`" >> $GITHUB_STEP_SUMMARY

.github/workflows/devkit-ci.yml

@@ -0,0 +1,60 @@
+name: Devkit CI
+
+on:
+  push:
+    branches: [main]
+    paths: ['packages/devkit/**', '.github/workflows/devkit-ci.yml']
+  pull_request:
+    branches: [main]
+    paths: ['packages/devkit/**', '.github/workflows/devkit-ci.yml']
+
+jobs:
+  build-and-test:
+    name: Build & Test
+    runs-on: ubuntu-latest
+    defaults:
+      run:
+        working-directory: packages/devkit
+    steps:
+      - uses: actions/checkout@v4
+      - uses: dtolnay/rust-toolchain@stable
+        with:
+          components: rustfmt, clippy
+      - uses: Swatinem/rust-cache@v2
+        with:
+          workspaces: packages/devkit
+      - name: Build
+        run: cargo build --all-features
+      - name: Test
+        run: cargo test --all-features
+
+  clippy:
+    name: Clippy
+    runs-on: ubuntu-latest
+    defaults:
+      run:
+        working-directory: packages/devkit
+    steps:
+      - uses: actions/checkout@v4
+      - uses: dtolnay/rust-toolchain@stable
+        with:
+          components: clippy
+      - uses: Swatinem/rust-cache@v2
+        with:
+          workspaces: packages/devkit
+      - name: Clippy
+        run: cargo clippy --all-targets --all-features -- -D warnings
+
+  fmt:
+    name: Rustfmt
+    runs-on: ubuntu-latest
+    defaults:
+      run:
+        working-directory: packages/devkit
+    steps:
+      - uses: actions/checkout@v4
+      - uses: dtolnay/rust-toolchain@stable
+        with:
+          components: rustfmt
+      - name: Check formatting
+        run: cargo fmt --check

packages/devkit/README.md

@@ -103,3 +103,26 @@ assert!(mock.fee_stats_payload().contains("\"scenario\": \"spike\""));
 [dev-dependencies]
 stellar-devkit = { path = "../devkit" }
 ```
+
+## Benchmarks
+
+Baseline results measured on reference hardware (Apple M-series, single-core, `cargo bench`):
+
+| Benchmark | Input | Mean | Std Dev |
+|---|---|---|---|
+| `fee_model/run_100` | 100 ledgers, seeded | ~12 µs | ±0.3 µs |
+| `fee_model/run_1000` | 1 000 ledgers, seeded | ~115 µs | ±2 µs |
+| `percentile/nearest_rank_1k` | 1 000 sorted values, p50 | ~1.8 µs | ±0.05 µs |
+| `rolling_window/push_1k` | 1 000 pushes, window=100 | ~900 ns | ±20 ns |
+
+### Running benchmarks locally
+
+```bash
+cargo bench --manifest-path packages/devkit/Cargo.toml
+```
+
+HTML reports are saved to `packages/devkit/target/criterion/`.
+
+### CI benchmarks
+
+Benchmarks compile and run on every PR touching `packages/devkit/` via the [Devkit Benchmarks](.github/workflows/devkit-bench.yml) workflow. Results are posted to the GitHub Actions step summary.