v0.3.0

Changelog

• 09fb4a5 Add pkg/control: PID, Smith predictor and step controllers as a library
• 6bf97e3 Clean up comments and extract comment-labeled blocks into functions
• ead568b Document the control library and move config notes into the README
• b681902 Drop metrics sent after the async recorder has stopped
• ce54495 Log gauge metrics at debug level instead of info
• 9d4314d Persist PATCH /pid changes to the active controller's config section
• eb1abed Remove comments and keep functions small
• c8f14a3 Remove dead receivemetrics handler, internal dev docs and editor config
• 97bd320 Remove the autopid self-tuning controller
• f73d292 Return dequeue errors from the switchable queue instead of spinning
• 31c3e61 Run the app controllers on top of pkg/control
• 3665fcf Stop the orchestrator and metrics poller gracefully on shutdown