refactor(web): source the search result bound from its protocol constant

`ConnectionHandle.sessionSearchResultLimit` mirrored
`SESSION_SEARCH_RESULT_LIMIT` as per-connection state, giving one fact two
homes in the same module and implying a transport-varying or server-negotiated
bound that the response schema's fixed `max` forbids. `SessionsService` now
reads the constant directly and its constructor drops the parameter; the
connection handle and its unreachable `/client` value re-export go away.

The import comes from the inline-safe wire layer rather than the connection
plugin's `/client` surface, which the bundle-purity gate rejects for value
imports.

packages/client/runtime/tests/sessions-service.spec.ts

@@ -23,7 +23,7 @@ interface Bench {
 function bench(): Bench {
   const ctx = new Context()
   const api = new FakeApiClient()
-  const svc = new SessionsService(ctx, api, 20)
+  const svc = new SessionsService(ctx, api)
   return { ctx, api, svc }
 }