docs(arch): ADR-066 — move from_jsonschema to alknet-http as HTTP-backed single-endpoint adapter

from_jsonschema was in alknet-call as a schema-only placeholder with a
NOT_FOUND handler — broken (an op in the registry needs a real handler)
and in the wrong crate (alknet-call has no HTTP client; a useful
from_jsonschema needs reqwest like from_openapi). ADR-066 moves it to
alknet-http as a real reqwest-backed single-endpoint adapter for
non-standard/non-OpenAPI REST endpoints, functionally similar to
from_openapi but one endpoint at a time. FromJsonSchema provenance
stays in alknet-call (now a handler-bearing leaf).

- New ADR-066 (supersedes ADR-017 §5 from_jsonschema clause + ADR-022
  FromJsonSchema row; both amended with strikethrough + pointer)
- Updated specs: call/client-and-adapters, call/README,
  call/operation-registry, http/http-adapters (new from_jsonschema
  section), http/overview, http/README, arch README + overview
- New task: tasks/http/adapters/from-jsonschema.md (depends on
  from-openapi; includes alknet-call cleanup of the broken placeholder)
- Old task tasks/call/client/from-jsonschema.md marked superseded

taskgraph validate: 116 tasks valid

tasks/call/client/from-jsonschema.md

@@ -7,6 +7,7 @@ scope: narrow
 risk: low
 impact: isolated
 level: implementation
+superseded_by: [http/adapters/from-jsonschema]
 ---
 
 ## Description