claude_runner_core 1.2.0

# Feature Doc Entity

### Scope

- **Purpose**: Document user-facing capabilities of the claude_runner_core library for consumers building Claude Code automation.
- **Responsibility**: Index of feature doc instances covering execution control, dry-run, command inspection, stdin file piping, and CLAUDECODE environment unsetting.
- **In Scope**: Execution mode design, dry-run semantics, describe/describe_compact output format, stdin_file piping, unset_claudecode default-on behavior.
- **Out of Scope**: Builder pattern design (→ `pattern/`), API contracts (→ `api/`), type definitions (→ `data_structure/`).

### Overview Table

| ID | Name | Purpose | Status |
|----|------|---------|--------|
| 001 | [Execution Control](001_execution_control.md) | Interactive vs. non-interactive execution modes | ✅ |
| 002 | [Dry Run](002_dry_run.md) | Command preview without process execution | ✅ |
| 003 | [Describe](003_describe.md) | Human-readable command inspection output | ✅ |
| 004 | [Isolated Subprocess Execution](004_run_isolated.md) | `run_isolated()` — temp-HOME subprocess spawn for OAuth token refresh; `IsolatedRunResult`, `RunnerError` types | ✅ |
| 005 | [Stdin File Piping](005_stdin_file.md) | `stdin_file` field — pipes file content as subprocess stdin via `with_stdin_file()` | ✅ |
| 006 | [CLAUDECODE Unsetting](006_unset_claudecode.md) | `unset_claudecode` field — removes `CLAUDECODE` env var before spawning (default-on) | ✅ |
| — | [procedure.md](procedure.md) | Workflow for creating and updating feature doc instances | ✅ |