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_deep_invariants_tests.rs

@@ -47,6 +47,7 @@ async fn invariant_tls_clienthello_truncation_exact_boundary_triggers_masking()
             1,
             1,
             1,
+            10,
             1,
             false,
             stats.clone(),
@@ -177,6 +178,7 @@ async fn invariant_direct_mode_partial_header_eof_is_error_not_bad_connect() {
             1,
             1,
             1,
+            10,
             1,
             false,
             stats.clone(),