Add GitHub Action with file-based caching, remove Redis dependency

.github/workflows/test.yml

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+name: Tests
+
+on:
+  push:
+    branches: [main, 'claude/**']
+  pull_request:
+    branches: [main]
+
+jobs:
+  unit-tests:
+    name: Unit Tests
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Setup Bun
+        uses: oven-sh/setup-bun@v2
+
+      - name: Install dependencies
+        run: bun install
+
+      - name: Run unit tests
+        run: bun test src/
+
+  # Integration test using the GitHub Action
+  test:
+    name: Test Worker ${{ matrix.index }}
+    runs-on: ubuntu-latest
+    strategy:
+      fail-fast: false
+      matrix:
+        index: [0, 1, 2]
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Setup Bun
+        uses: oven-sh/setup-bun@v2
+
+      - name: Install dependencies
+        run: bun install
+
+      - name: Split tests
+        id: split
+        uses: ./
+        with:
+          command: split
+          pattern: 'tests/dummy/*.test.ts'
+          total: 3
+          index: ${{ matrix.index }}
+          cache-key: integration-tests
+
+      - name: Show assigned tests
+        run: echo "Worker ${{ matrix.index }} running:${{ steps.split.outputs.tests }}"
+
+      - name: Run tests
+        if: steps.split.outputs.tests != ''
+        run: bun test ${{ steps.split.outputs.tests }} --reporter=junit --reporter-outfile=junit-${{ matrix.index }}.xml
+
+      - name: Convert JUnit to timing JSON
+        if: steps.split.outputs.tests != ''
+        uses: ./
+        with:
+          command: convert
+          from: junit-${{ matrix.index }}.xml
+          to: timing-${{ matrix.index }}.json
+
+      - name: Upload timing artifact
+        if: always()
+        uses: actions/upload-artifact@v4
+        with:
+          name: timing-${{ matrix.index }}
+          path: timing-${{ matrix.index }}.json
+
+  save-timings:
+    name: Save Timings
+    needs: test
+    if: always()
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      - uses: actions/download-artifact@v4
+
+      - name: Show downloaded artifacts
+        run: find . -name "*.json" -type f
+
+      - name: Merge timings
+        uses: ./
+        with:
+          command: merge
+          prefix: 'timing-*/timing-'
+          cache-key: integration-tests
+
+      - name: Show saved timings
+        run: cat .fairsplice-timings.json

CLAUDE.md

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+# CLAUDE.md
+
+This file provides guidance to Claude Code (claude.ai/code) when working with code in this repository.
+
+## Project Overview
+
+Fairsplice is a TypeScript/Bun CLI tool and GitHub Action that optimizes test distribution across parallel workers. It provides CircleCI-style test splitting based on historical timing data for GitHub Actions.
+
+## Commands
+
+```bash
+# Run locally
+bun run index.ts
+
+# Run all tests
+bun test
+
+# Run tests in src directory
+bun test src/
+
+# Run a specific test file
+bun test src/lib/splitFiles.test.ts
+
+# Compile to standalone binary
+bun build ./index.ts --compile --outfile fairsplice
+```
+
+## Architecture
+
+**Entry Point**: `index.ts` - CLI with three commands: `split`, `convert`, `merge`
+
+**Source Structure**:
+- `src/commands/` - CLI command implementations
+  - `split.ts` - Distributes test files across workers using bin packing
+  - `merge.ts` - Aggregates timing JSON files and updates history
+  - `convert.ts` - Converts JUnit XML to timing JSON
+- `src/lib/` - Core algorithms
+  - `splitFiles.ts` - Greedy bin packing algorithm (assigns heaviest tests first to balance workload)
+  - `junit.ts` - JUnit XML parser using `fast-xml-parser`
+  - `average.ts` - Timing averaging utility
+- `src/backend/` - Storage layer
+  - `fileStorage.ts` - JSON-based timing persistence with rolling window of last 10 timings per file
+- `src/config.ts` - Constants (`NUMBER_OF_TIMINGS_TO_KEEP=10`, `DEFAULT_TIMING_IF_MISSING=10000ms`)
+
+**GitHub Action**: `action.yml` - Composite action wrapping the CLI with automatic cache handling
+
+**Data Flow**:
+1. `split` loads cached timings, globs test files, applies bin packing, outputs bucket assignments
+2. Tests run in parallel workers, each outputting JUnit XML
+3. `convert` transforms JUnit XML to timing JSON (one per worker)
+4. `merge` aggregates timing JSONs into cached timings history
+
+## Testing
+
+Tests are co-located with source files (`*.test.ts`). Test fixtures for JUnit parsing are in `src/lib/fixtures/`.
+
+The CI workflow (`.github/workflows/test.yml`) runs unit tests plus a 3-worker integration test that exercises the full split→run→convert→merge pipeline.