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/client_masking_redteam_expected_fail_tests.rs

@@ -48,6 +48,7 @@ fn build_harness(secret_hex: &str, mask_port: u16) -> RedTeamHarness {
         1,
         1,
         1,
+        10,
         1,
         false,
         stats.clone(),
@@ -237,6 +238,7 @@ async fn redteam_03_masking_duration_must_be_less_than_1ms_when_backend_down() {
             1,
             1,
             1,
+            10,
             1,
             false,
             Arc::new(Stats::new()),
@@ -477,6 +479,7 @@ async fn measure_invalid_probe_duration_ms(delay_ms: u64, tls_len: u16, body_sen
             1,
             1,
             1,
+            10,
             1,
             false,
             Arc::new(Stats::new()),
@@ -550,6 +553,7 @@ async fn capture_forwarded_probe_len(tls_len: u16, body_sent: usize) -> usize {
             1,
             1,
             1,
+            10,
             1,
             false,
             Arc::new(Stats::new()),