Tiltmeter 0.1.0rc1

First release candidate, published to TestPyPI only.

Added

• Learn the shape of JSON responses from real traffic and compare every check with a
  rolling baseline of recent responses, with no spec required.
• Classify changes as breaking, warning or info: removed, newly optional, retyped and newly
  nullable fields, new enum values, status and content-type changes, latency regressions
  and new fields, with hints for probable renames.
• The tiltmeter command with init, check, watch, history, show, schema,
  explain and serve, and exit codes for CI.
• An MCP server with has_drifted, get_schema, get_changes, list_endpoints,
  check_api and check_all, plus endpoint and schema resources.
• Optional drift explanations written by Claude through LangChain, using structured
  outputs.
• Slack and webhook notifications.
• A local SQLite history with content-addressed shapes and retention.