feat(adminui): author + configure the Sql driver in /raw

The read-only Sql driver's runtime factory/probe and tag-side editors were
wired, but the AdminUI could not author the DRIVER: the /raw "New driver" type
list, the DriverConfigModal switch, and the legacy identity dropdown all omitted
Sql, and no SqlDriverForm existed. Live-driving the AdminUI surfaced this.

- Add SqlDriverForm.razor over the SqlDriverConfigDto shape: Provider
  (SqlServer-only in v1), required connectionStringRef (an env-var NAME, not a
  connection string — label is explicit), optional poll/operation/command
  timeouts, maxConcurrentGroups, nullIsBad. Enums serialize by NAME via
  JsonStringEnumConverter; a connection-string literal can never be authored
  (no such field is collected); rawTags (composer-owned) + allowWrites (inert,
  read-only v1) are never emitted.
- Wire Sql into DriverConfigModal switch, RawDriverTypeDialog type list, and
  DriverIdentitySection legacy dropdown.
- Add SqlDriverFormContractTests: the exact JSON the form emits constructs a
  driver through the real factory, missing connectionStringRef is rejected, and
  provider round-trips as the "SqlServer" name (never an ordinal).

Claude-Session: https://claude.ai/code/session_01GASWkNEi68FSCtvr6rLoEW

src/Server/ZB.MOM.WW.OtOpcUa.AdminUI/Components/Shared/Drivers/DriverIdentitySection.razor

@@ -36,6 +36,7 @@
                         <option value="Focas">Focas</option>
                         <option value="OpcUaClient">OpcUaClient</option>
                         <option value="GalaxyMxGateway">Galaxy</option>
+                        <option value="Sql">Sql</option>
                     </InputSelect>
                     <div class="form-text">Cannot be changed after creation — drives the actor type that owns this instance.</div>
                 </div>