Add Wahoo activity sync with provider-agnostic framework

Provider-agnostic sync framework + Wahoo as first implementation:

Framework (apps/journal/app/lib/sync/):
- SyncProvider interface for OAuth2, webhooks, import, conversion
- Provider registry for settings UI iteration
- Generic sync_connections + sync_imports tables
- Token storage with auto-refresh

Wahoo provider:
- OAuth2 with workouts_read, user_read, offline_data scopes
- Webhook-based auto-import (workout_summary events)
- Manual import page with pagination
- FIT→GPX conversion via fit-file-parser
- Webhook token verification

Routes:
- /api/sync/connect/:provider — OAuth redirect
- /api/sync/callback/:provider — OAuth callback
- /api/sync/disconnect/:provider — remove connection
- /api/sync/webhook/:provider — webhook receiver
- /sync/import/:provider — manual import page

Settings: Connected Services section with per-provider connect/disconnect

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

apps/journal/app/routes/api.sync.disconnect.$provider.ts

@@ -0,0 +1,16 @@
+import { redirect, data } from "react-router";
+import type { Route } from "./+types/api.sync.disconnect.$provider";
+import { getSessionUser } from "~/lib/auth.server";
+import { getProvider } from "~/lib/sync/registry";
+import { deleteConnection } from "~/lib/sync/connections.server";
+
+export async function action({ params, request }: Route.ActionArgs) {
+  const user = await getSessionUser(request);
+  if (!user) return redirect("/auth/login");
+
+  const provider = getProvider(params.provider);
+  if (!provider) return data({ error: "Unknown provider" }, { status: 404 });
+
+  await deleteConnection(user.id, provider.id);
+  return redirect("/settings");
+}