docs: add CLAUDE.md with development guidelines (#1)

- Add overview of package purpose (PII/PHI detection and redaction)
- Add quick commands for installation, testing, and usage
- Add supported entity types table
- Add links to related projects

Author: abrichr

CLAUDE.md

@@ -0,0 +1,103 @@
+# Claude Code Instructions for openadapt-privacy
+
+## Overview
+
+**openadapt-privacy** provides PII/PHI detection and redaction for GUI automation data. It protects sensitive information (emails, phone numbers, SSNs, credit cards, dates) in text, images, and nested dictionaries.
+
+Key responsibilities:
+- Detect personally identifiable information using NER models (Presidio)
+- Redact PII from text, images, and structured data
+- Support custom entity detection and scrubbing rules
+- Integrate with openadapt-capture recording pipelines
+
+**Always use PRs, never push directly to main**
+
+## Quick Commands
+
+```bash
+# Install with Presidio (recommended)
+uv add "openadapt-privacy[presidio]"
+
+# Download spaCy model for NER
+python -m spacy download en_core_web_trf
+
+# Run tests
+uv run pytest tests/ -v
+
+# Scrub text
+uv run python -c "
+from openadapt_privacy import PresidioScrubber
+scrubber = PresidioScrubber()
+text = 'Contact John Smith at john@example.com or 555-123-4567'
+print(scrubber.scrub_text(text))
+"
+
+# Scrub dictionary
+uv run python -c "
+from openadapt_privacy import scrub_dict, PresidioScrubber
+scrubber = PresidioScrubber()
+data = {'name': 'John Smith', 'email': 'john@example.com'}
+print(scrub_dict(data, scrubber))
+"
+```
+
+## Architecture
+
+```
+openadapt_privacy/
+  base.py              # Base classes: Scrubber, ScrubbingProvider
+  config.py            # PrivacyConfig dataclass
+  loaders.py           # Recording/Action/Screenshot loaders
+  pipelines/dicts.py   # Dictionary scrubbing utilities
+  providers/presidio.py # PresidioScrubber (primary implementation)
+```
+
+## Key Components
+
+### PresidioScrubber
+Primary scrubber using Presidio NER and spaCy:
+- Detects: PERSON, EMAIL_ADDRESS, PHONE_NUMBER, US_SSN, CREDIT_CARD, DATE_TIME, LOCATION
+- `scrub_text(text)` - Redact PII from text
+- `scrub_image(image)` - OCR + redact PII regions
+
+### Text Scrubbing
+```python
+from openadapt_privacy import PresidioScrubber
+scrubber = PresidioScrubber()
+text = "Contact John Smith at john@example.com"
+# Output: "Contact <PERSON> at <EMAIL_ADDRESS>"
+print(scrubber.scrub_text(text))
+```
+
+### Dictionary Scrubbing
+```python
+from openadapt_privacy import scrub_dict, PresidioScrubber
+scrubber = PresidioScrubber()
+action = {"text": "Email john@example.com", "title": "User John Smith"}
+scrubbed = scrub_dict(action, scrubber)
+```
+
+## Supported Entity Types
+
+| Entity | Input | Output |
+|--------|-------|--------|
+| PERSON | John Smith | <PERSON> |
+| EMAIL_ADDRESS | john@example.com | <EMAIL_ADDRESS> |
+| PHONE_NUMBER | 555-123-4567 | <PHONE_NUMBER> |
+| US_SSN | 923-45-6789 | <US_SSN> |
+| CREDIT_CARD | 4532-1234-5678-9012 | <CREDIT_CARD> |
+| DATE_TIME | 01/15/1985 | <DATE_TIME> |
+| LOCATION | Toronto, ON | <LOCATION> |
+
+## Testing
+
+```bash
+uv run pytest tests/ -v
+```
+
+## Related Projects
+
+- [openadapt-capture](https://github.com/OpenAdaptAI/openadapt-capture) - GUI interaction capture
+- [openadapt-ml](https://github.com/OpenAdaptAI/openadapt-ml) - Train models on captures
+- [openadapt-viewer](https://github.com/OpenAdaptAI/openadapt-viewer) - Visualization components
+- [Presidio](https://github.com/microsoft/presidio) - PII detection and redaction