ci: fix duplicate runs and combine fmt/clippy/test

- Remove claude/** from push triggers (PRs handle this)
- Add concurrency to cancel in-progress runs
- Combine check, fmt, clippy, test into single CI job

Reduces number of checks from 7 to 4 and eliminates duplicates.

Author: claude

.github/workflows/ci.yml

@@ -2,9 +2,13 @@ name: CI
 
 on:
   push:
-    branches: [main, "claude/**"]
-  pull_request:
     branches: [main]
+  pull_request:
+
+# Cancel in-progress runs for same PR/branch
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: true
 
 permissions:
   contents: read
@@ -14,47 +18,20 @@ env:
   RUST_BACKTRACE: 1
 
 jobs:
-  check:
-    name: Check
-    runs-on: ubuntu-latest
-    steps:
-      - uses: actions/checkout@v4
-      - uses: dtolnay/rust-toolchain@stable
-      - uses: Swatinem/rust-cache@v2
-      - name: Check
-        run: cargo check --workspace --all-targets
-
-  fmt:
-    name: Rustfmt
+  ci:
+    name: CI
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v4
       - uses: dtolnay/rust-toolchain@stable
         with:
-          components: rustfmt
-      - name: Check formatting
-        run: cargo fmt --all -- --check
-
-  clippy:
-    name: Clippy
-    runs-on: ubuntu-latest
-    steps:
-      - uses: actions/checkout@v4
-      - uses: dtolnay/rust-toolchain@stable
-        with:
-          components: clippy
+          components: rustfmt, clippy
       - uses: Swatinem/rust-cache@v2
+      - name: Format
+        run: cargo fmt --all -- --check
       - name: Clippy
         run: cargo clippy --workspace --all-targets -- -D warnings
-
-  test:
-    name: Test
-    runs-on: ubuntu-latest
-    steps:
-      - uses: actions/checkout@v4
-      - uses: dtolnay/rust-toolchain@stable
-      - uses: Swatinem/rust-cache@v2
-      - name: Run tests
+      - name: Test
         run: cargo test --workspace
 
   build: