fix: move tg_connect to general, rustfmt upstream, fix UpstreamManager::new tests

- Relocate tg_connect from [timeouts] to [general] with validation and docs updates.
- Apply rustfmt to per-attempt upstream connect timeout expression in upstream.rs.
- Pass tg_connect_timeout_secs in all UpstreamManager::new test call sites.
- Wire hot reload and runtime snapshot to general.tg_connect.

src/proxy/tests/direct_relay_security_tests.rs

@@ -1302,6 +1302,7 @@ async fn direct_relay_abort_midflight_releases_route_gauge() {
         1,
         1,
         1,
+        10,
         1,
         false,
         stats.clone(),
@@ -1408,6 +1409,7 @@ async fn direct_relay_cutover_midflight_releases_route_gauge() {
         1,
         1,
         1,
+        10,
         1,
         false,
         stats.clone(),
@@ -1529,6 +1531,7 @@ async fn direct_relay_cutover_storm_multi_session_keeps_generic_errors_and_relea
         1,
         1,
         1,
+        10,
         1,
         false,
         stats.clone(),
@@ -1761,6 +1764,7 @@ async fn negative_direct_relay_dc_connection_refused_fails_fast() {
         1,
         100,
         5000,
+        10,
         3,
         false,
         stats.clone(),
@@ -1851,6 +1855,7 @@ async fn adversarial_direct_relay_cutover_integrity() {
         1,
         100,
         5000,
+        10,
         3,
         false,
         stats.clone(),