feat(cli): Add af api command for direct Airflow REST API access

[kaxil]

Summary

Add a generic af api command that provides direct access to any Airflow REST API endpoint, similar to gh api for GitHub. This enables users and AI agents to access any API endpoint not covered by the high-level CLI commands.

Features

• HTTP Methods: GET, POST, PATCH, PUT, DELETE via -X flag
• Query Parameters: -F key=value (auto type conversion) or -f key=value (raw string)
• JSON Body: --body '{...}' for complex payloads
• Endpoint Discovery: --endpoints lists available paths, --filter narrows results
• OpenAPI Spec: --spec fetches full API spec
• Response Headers: -i includes status code and headers
• Raw Endpoints: --raw bypasses version prefix (for /health, etc.)
• Version Handling: Automatic AF2 (/api/v1) vs AF3 (/api/v2) detection

Usage Examples

# Discover available endpoints
af api --endpoints
af api --endpoints --filter variable

# Basic operations
af api dags
af api dags -F limit=10 -F only_active=true
af api dags/my_dag

# Create/modify resources
af api variables -X POST -F key=my_var -f value="my value"
af api dags/my_dag -X PATCH -F is_paused=false
af api variables/old_var -X DELETE

# Debug with headers
af api dags -i

# Access non-versioned endpoints
af api health --raw

Design Decisions

Why add to adapter vs direct HTTP?
The adapter pattern already handles authentication (token/basic auth via _setup_auth()) and version prefixes. Adding raw_request() to the base adapter keeps the architecture consistent.

Why --endpoints instead of requiring jq?
Not all users have jq installed, and endpoint discovery is a common operation. The --filter option makes it easy to find specific endpoints without external tools.

Why warn on connections endpoint?
Unlike af config connections which filters passwords, af api connections returns raw API responses. The warning directs users to the filtered alternative.

Files Changed

File	Change
adapters/base.py	Add raw_request() and _delete() methods
cli/api.py	New command module (357 lines)
cli/main.py	Register the command
tests/test_cli_api.py	Unit tests (34 tests)
tests/integration/test_cli_api.py	Integration tests (17 tests)
README.md	Document the command
skills/airflow/SKILL.md	Add quick reference
skills/airflow/api-reference.md	Full reference (progressive disclosure)

[jlaneve]

@kaxil wdyt about af api ls or something instead of the af api --endpoints? the flag feels a bit odd