feat: integrate claude-code-base-action as local subaction (#285)

* feat: integrate claude-code-base-action as local subaction

- Copy claude-code-base-action into base-action/ directory
- Update action.yml to reference ./base-action instead of external repo
- Preserve complete base action structure for future refactoring

This eliminates the external dependency while maintaining modularity.

* feat: consolidate CI workflows and add version bump workflow

- Move base-action test workflows to main .github/workflows/
- Update workflow references to use ./base-action
- Add CI jobs for base-action (test, typecheck, prettier)
- Add bump-claude-code-version workflow for base-action
- Remove redundant .github directory from base-action

This consolidates all CI workflows in one place while maintaining
full test coverage for both the main action and base-action.

* tsc

* copy again

* fix tests

* fix: use absolute path for base-action reference

Replace relative path ./base-action with ${{ github.action_path }}/base-action
to ensure the action works correctly when used in other repositories.

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

* fix: inline base-action execution to support usage in other repos

Replace uses: ./base-action with direct shell execution since GitHub Actions
doesn't support dynamic paths in composite actions. This ensures the action
works correctly when used in other repositories.

Changes:
- Install Claude Code globally before execution
- Run base-action's index.ts directly with bun
- Pass all required INPUT_* environment variables
- Maintain base-action for future separate publishing

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

---------

Co-authored-by: Claude <noreply@anthropic.com>

base-action/CLAUDE.md

@@ -0,0 +1,60 @@
+# CLAUDE.md
+
+## Common Commands
+
+### Development Commands
+
+- Build/Type check: `bun run typecheck`
+- Format code: `bun run format`
+- Check formatting: `bun run format:check`
+- Run tests: `bun test`
+- Install dependencies: `bun install`
+
+### Action Testing
+
+- Test action locally: `./test-local.sh`
+- Test specific file: `bun test test/prepare-prompt.test.ts`
+
+## Architecture Overview
+
+This is a GitHub Action that allows running Claude Code within GitHub workflows. The action consists of:
+
+### Core Components
+
+1. **Action Definition** (`action.yml`): Defines inputs, outputs, and the composite action steps
+2. **Prompt Preparation** (`src/index.ts`): Runs Claude Code with specified arguments
+
+### Key Design Patterns
+
+- Uses Bun runtime for development and execution
+- Named pipes for IPC between prompt input and Claude process
+- JSON streaming output format for execution logs
+- Composite action pattern to orchestrate multiple steps
+- Provider-agnostic design supporting Anthropic API, AWS Bedrock, and Google Vertex AI
+
+## Provider Authentication
+
+1. **Anthropic API** (default): Requires API key via `anthropic_api_key` input
+2. **AWS Bedrock**: Uses OIDC authentication when `use_bedrock: true`
+3. **Google Vertex AI**: Uses OIDC authentication when `use_vertex: true`
+
+## Testing Strategy
+
+### Local Testing
+
+- Use `act` tool to run GitHub Actions workflows locally
+- `test-local.sh` script automates local testing setup
+- Requires `ANTHROPIC_API_KEY` environment variable
+
+### Test Structure
+
+- Unit tests for configuration logic
+- Integration tests for prompt preparation
+- Full workflow tests in `.github/workflows/test-action.yml`
+
+## Important Technical Details
+
+- Uses `mkfifo` to create named pipes for prompt input
+- Outputs execution logs as JSON to `/tmp/claude-execution-output.json`
+- Timeout enforcement via `timeout` command wrapper
+- Strict TypeScript configuration with Bun-specific settings