[Ingest] Route scraping through an optional V2Ray/Xray proxy (Telegram in Iran)

Telegram and some sources are filtered in Iran. .NET cannot speak vmess/vless/trojan, so add an Xray sidecar (compose service 'xray', behind the 'proxy' profile) that converts the admin's config into a local SOCKS5 proxy (xray:10808). New ScrapeHttpClients provider builds a proxied or direct HttpClient (WebProxy supports socks5/socks4/http) cached per proxy URL; all five ingestion sources (Telegram/Bale/Divar/Medjobs/Websites) now use it. Admin settings gain IngestProxyEnabled + IngestProxyUrl (migration; UI under sources). Added deploy/xray/config.json template + README with vmess/vless/trojan examples.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/JobsMedical.Web/Services/Scraping/ScrapeHttpClients.cs

@@ -0,0 +1,55 @@
+using System.Collections.Concurrent;
+using System.Net;
+using JobsMedical.Web.Models;
+
+namespace JobsMedical.Web.Services.Scraping;
+
+/// <summary>
+/// Supplies the HttpClient used by ingestion sources, optionally routed through a proxy.
+///
+/// Telegram (t.me) and some other sources are filtered in Iran, so the admin can point
+/// ingestion at a local proxy that an Xray/V2Ray client sidecar exposes (e.g.
+/// <c>socks5://xray:10808</c>). .NET's WebProxy understands <c>socks5://</c>, <c>socks4://</c>
+/// and <c>http://</c> schemes, so the same code path covers all of them.
+///
+/// Clients are cached per proxy descriptor (singleton). Changing the proxy in admin settings
+/// makes the next run pick up a new client; the old one is disposed.
+/// </summary>
+public sealed class ScrapeHttpClients : IDisposable
+{
+    private readonly ConcurrentDictionary<string, HttpClient> _cache = new();
+
+    /// <summary>The HttpClient for the given settings — proxied when enabled, direct otherwise.</summary>
+    public HttpClient For(AppSetting s)
+    {
+        var key = (s.IngestProxyEnabled && !string.IsNullOrWhiteSpace(s.IngestProxyUrl))
+            ? s.IngestProxyUrl.Trim()
+            : "direct";
+
+        // Drop stale clients if the proxy URL changed (keep only "direct" + the current proxy).
+        foreach (var k in _cache.Keys)
+            if (k != "direct" && k != key && _cache.TryRemove(k, out var stale))
+                stale.Dispose();
+
+        return _cache.GetOrAdd(key, Build);
+    }
+
+    private static HttpClient Build(string key)
+    {
+        var handler = new HttpClientHandler { AutomaticDecompression = DecompressionMethods.All };
+        if (key != "direct")
+        {
+            handler.Proxy = new WebProxy(key);   // socks5:// | socks4:// | http://
+            handler.UseProxy = true;
+        }
+        var c = new HttpClient(handler) { Timeout = TimeSpan.FromSeconds(20) };
+        c.DefaultRequestHeaders.UserAgent.ParseAdd("Mozilla/5.0 (compatible; HamkadrBot/1.0)");
+        return c;
+    }
+
+    public void Dispose()
+    {
+        foreach (var c in _cache.Values) c.Dispose();
+        _cache.Clear();
+    }
+}