Fix SMART data and site latency checking issues

- Add sudo to disk collector smartctl commands for proper SMART data access
- Add reqwest dependency with blocking feature for HTTP site checks
- Replace curl-based site latency with reqwest HTTP client implementation
- Maintain 2-second connect timeout and 5-second total timeout
- Fix disk health UNKNOWN status by enabling proper SMART permissions
- Fix nginx site timeout issues by using proper HTTP client with redirect support

agent/Cargo.toml

@@ -18,4 +18,5 @@ tracing-subscriber = { workspace = true }
 lettre = { workspace = true }
 gethostname = { workspace = true }
 toml = { workspace = true }
-async-trait = "0.1"
+async-trait = "0.1"
+reqwest = { version = "0.11", features = ["json", "blocking"] }