feat(sub): add Happ client integration, routing presets, and app management (#6434)

* feat(sub): add Happ client integration, routing presets, and app management

Implement comprehensive Happ proxy client integration according to official developer specifications.

- Fix header emission on disabled routing and hidden settings to send explicit '0' headers rather than omitting, allowing Happ clients to reset cached settings.
- Add support for 'happ://routing/off' deeplink in routing validation.
- Preserve '?serverDescription=' query parameters in link fragments without escaping to support Happ server subtitles across VMess, VLESS, Trojan and SS.
- Add Happ application management headers: ProviderID, New-Url, Fallback-Url, Sub-Info banners, Sub-Expire notifications, No-Limit mode, hardware ID enforcement, TUN modes/types, route exclusions, APNS exclusions, and per-app proxy settings.
- Add curated routing presets (Iran Bypass, China Direct, AdBlock, Global) and interactive visual rule generator in frontend settings.
- Synchronize all 13 translation locales with native Persian, Russian, and Chinese translations.

* fix(sub): keep Happ header overrides behind the auto-detect opt-in

The Routing-Enable/Hide-Settings off values were emitted on the
User-Agent alone, so every panel that upgraded would push
"Routing-Enable: 0" — documented by happ.su as disabling routing
globally — to every Happ client without the operator enabling anything.
They now ride subHappAutoDetect like every other Happ header.

Two further mismatches against the vendor spec:

- serverDescription was written as a key of the VMess base64 JSON
  object. happ.su documents it as a "#Title?serverDescription=<base64>"
  link parameter or a JSON "meta" entry, so the caption never reached
  Happ while every other VMess consumer received an unknown key.
  Dropped rather than moved: emitting the documented form is unsafe
  here because our own parser base64-decodes the whole VMess body
  (internal/util/link/outbound.go).

- The TUN Mode dropdown stored the literal "default", forwarded as
  "Tun-Mode: default", where happ.su documents system|gvisor only. It
  now stores the unset value so no header is sent. TUN Type "default"
  is a documented value and is unchanged.

Each fix carries a test that fails without it.

internal/sub/remote_routing.go

@@ -369,6 +369,9 @@ func normalizeHappRouting(body []byte) (string, error) {
 		}
 		return "happ://routing/onadd/" + base64.StdEncoding.EncodeToString(compact), nil
 	}
+	if text == "happ://routing/off" {
+		return text, nil
+	}
 	if strings.ContainsAny(text, "\r\n") {
 		return "", errors.New("Happ deeplink must be a single line")
 	}