Demo, migration guide, and config file rename to fastcs.yaml

[gilesknap]

Parent

#351

What to build

Final integration slice: rename the bundled demo config from controller.yaml to fastcs.yaml, update the demo to host two controllers so the multi-controller feature is visible out of the box, ensure the launcher does not hard-code the filename, regenerate the JSON schema for the new dict-by-id options, and document manual migration for existing FastCS apps.

Scope:

• Rename src/fastcs/demo/controller.yaml → src/fastcs/demo/fastcs.yaml.
• Demo fastcs.yaml declares two controllers (e.g. two TemperatureController instances with distinct ids and connection settings) so the feature is exercised end-to-end on python -m fastcs.demo.
• Launcher does not hard-code fastcs.yaml as a filename — the path remains a CLI argument.
• launch ... schema regenerated and committed (src/fastcs/demo/schema.json) reflecting the new dict-by-id controllers: block.
• Changelog entry covering the breaking change with manual migration guidance:
  • controller.yaml → fastcs.yaml rename
  • controller: block → controllers: { <id>: { type: ..., controller: ... } } form
  • EpicsIOCOptions.pv_prefix removed; the id is the prefix
  • Single-class type: inference allowed
• Documentation updated to use the new filename and dict form throughout examples.

Out of scope (per the parent PRD): tutorial rewrite, useful defaults for omitted transport:, super-PVI parent record, automated migration tooling, per-controller GUI/docs overrides, per-transport id aliases, multi-process deployments.

User stories from #351 covered: 28, 29, 30, 31.

Acceptance criteria

• src/fastcs/demo/fastcs.yaml exists with two configured controllers; old controller.yaml removed
• python -m fastcs.demo runs end-to-end and serves both controllers over the configured transports
• Launcher accepts any filename via CLI argument; nothing hard-codes fastcs.yaml
• src/fastcs/demo/schema.json regenerated and matches the new dict-by-id options
• Changelog entry documents the breaking change and manual migration steps
• Documentation examples use fastcs.yaml and the dict form
• Full test suite stays green; docs build stays green

Blocked by

• EPICS CA multi-root softioc with id-based PV prefix #354
• EPICS PVA multi-root with N PVI roots #355
• GraphQL combined schema with id-keyed top-level Query fields #356
• Tango multi-device with id in device name #357
• GUI and docs emission: one file per controller plus index file #358