First milestone of the LLM-fallback plan (docs/plans/llm-fallback-aliases.md).
Introduces the `mana/<class>` namespace; the registry parses + validates
aliases.yaml at startup and reloads on demand. Schema-rejects empty
chains, missing provider prefixes, alias names outside the reserved
namespace, default→unknown references, etc.
Reload semantics: parse error keeps the previous good state in memory
so a typo + SIGHUP doesn't take the service down.
5 aliases ship with the initial config: fast-text, long-form, structured,
reasoning, vision. Each chain ends with a cloud provider so the system
keeps working when the GPU server is offline.
32 unit tests covering happy path, schema validation, namespace check,
reload safety, and a guard that the shipped aliases.yaml itself parses.
M2 (health-cache + probe-loop) and M3 (router fallback execution) build
on this; aliases are not yet wired into the request path.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
