Switch the OpenAPI document used by the SDK build (and `bun dev generate`)
from the legacy Hono backend to `OpenApi.fromApi(PublicApi)`.
The Effect HttpApi backend already covers every Hono route — the bridge
test in `httpapi-bridge.test.ts` audits this — and `PublicApi` already
applies the legacy-shape transforms (instance query params, optional-null
stripping, SSE schemas, component renames). The spec-emitting path was
the last piece still rooted in Hono.
The Hono path is preserved as `Server.openapiHono()` and `bun dev generate
--hono` so reviewers can diff the two outputs while the Hono backend
lingers; both go away with the Hono backend itself.
Verified the new default matches the previous `--httpapi` output
byte-for-byte and the SDK build round-trips cleanly.
Moves effect logging, observability, runtime utilities, flags, installation
version info, and process utilities from opencode to core package. This
enables better code sharing across packages and establishes core as the
single source of truth for foundational utilities.
All internal imports updated to use @opencode-ai/core paths for consistency.
Kit Langton