Apple shell: carry every server request through one HTTP adapter

[JacobStephens2]

Summary

The Apple shell (iOS and macOS, through CascadeShared) now carries every sync-server request on one code path. The core decides what each request means.

 AppStore.apply(effect)
-  case .pushListening / .sendSignInLink / .verifySignInToken /
-       .revokeSession / .deleteServerListening / .deleteServerAccount
-    carry(effect)            # switch per request → SyncApi typed call → one of 7 settles
+  case .serverRequest(let request)
+    carry(request)
+      Task @MainActor
+        dispatch(await ServerCarrier.send(request))   # → .serverResponse(id, status, body)

 CascadeShared/Sync/
-├── SyncApi.swift        # typed client, VerifyResponse, ListeningResponse, SyncError
+├── ServerCarrier.swift  # sends method + base URL + path, Bearer when given, body verbatim
+├── SyncConfig.swift     # base URL / "sync available" (unchanged, moved)
 └── AccountControlsView.swift   # delete buttons now make the fresh UUID

• ServerCarrier.send returns status 0 in these cases: no sync server configured, a bad URL, a non-HTTP response, or a thrown error (network, the 15 s timeout, cancellation).
• The sign-out revoke is now settled like every other request.
• Dto.swift mirrors the core's wire:
  • Effect.serverRequest(ServerRequest) and Command.serverResponse(id:status:body:).
  • newDeviceId on deleteListeningData / deleteAccount.
  • Optional platform on requestSignInLink.
• The watch app's phone↔watch protocol is untouched.

Evidence

• cargo test: every suite passes. The core is unchanged on this branch.
• Apple build (CI): passes. Run 37161662889 builds CascadeMac, CascadeiOS and CascadeWatch against the new core. The authoring host has no Swift toolchain, so this is the only compile.
• Not yet checked by hand: sign-in by link, a listening sync, sign-out, delete listening data and delete account against the sync server.
• I checked the JSON wire shapes by reading them against effect.rs, command.rs and server.rs.

Merge Danger

Door: two-way

Revert the commits to bring back the typed client.

Blast Radius: account-sync

If it is wrong, sign-in, listening sync and the delete actions on iOS and macOS break. Playback, timers and the watch app don't touch this path.

Unaddressed findings

Standards

• Speculative Generality: platform on requestSignInLink is never sent by this shell. Kept. Issue Apple shell: carry every server request through one HTTP adapter #61 asks for the DTO to carry it, and it matches the core's wire. Only the Windows shell needs a link hand-off.
• Duplicated Code: UUID().uuidString appears inline in both delete buttons. Kept. The issue says the fresh UUID is "made when the user asks", and a helper for one expression adds little.

Spec

• The Apple shell sends no platform with the sign-in link request. Intended: "behave as before on this platform". Apple handles the link through its universal link.
• Content-Type: application/json is now set only when there is a body. Kept. The server reads JSON only on routes that take a body (axum Json extractor), and bodiless DELETEs and logout don't check the header.
• Hand-testing against the sync server has not been done. No Apple toolchain or device on the authoring host. CI builds it, and the manual run is left for review.

Closes #61

🤖 Generated with Claude Code