Zeroize for key + log refactor + fix tests

- Fixed tests that failed to compile due to mismatched generic parameters of HandshakeResult:
  - Changed `HandshakeResult<i32>` to `HandshakeResult<i32, (), ()>`
  - Changed `HandshakeResult::BadClient` to `HandshakeResult::BadClient { reader: (), writer: () }`

- Added Zeroize for all structures holding key material:
  - AesCbc – key and IV are zeroized on drop
  - SecureRandomInner – PRNG output buffer is zeroized on drop; local key copy in constructor is zeroized immediately after being passed to the cipher
  - ObfuscationParams – all four key‑material fields are zeroized on drop
  - HandshakeSuccess – all four key‑material fields are zeroized on drop

- Added protocol‑requirement documentation for legacy hashes (CodeQL suppression) in hash.rs (MD5/SHA‑1)

- Added documentation for zeroize limitations of AesCtr (opaque cipher state) in aes.rs

- Implemented silent‑mode logging and refactored initialization:
  - Added LogLevel enum to config and CLI flags --silent / --log-level
  - Added parse_cli() to handle --silent, --log-level, --help
  - Restructured main.rs initialization order: CLI → config load → determine log level → init tracing
  - Errors before tracing initialization are printed via eprintln!
  - Proxy links (tg://) are printed via println! – always visible regardless of log level
  - Configuration summary and operational messages are logged via info! (suppressed in silent mode)
  - Connection processing errors are lowered to debug! (hidden in silent mode)
  - Warning about default tls_domain moved to main (after tracing init)

Co-Authored-By: brekotis <93345790+brekotis@users.noreply.github.com>

config.toml

@@ -6,8 +6,13 @@ show_link = ["hello"]
 [general]
 prefer_ipv6 = false
 fast_mode = true
-use_middle_proxy = false
-# ad_tag = "..."
+use_middle_proxy = true
+ad_tag = "00000000000000000000000000000000"
+
+# Log level: debug | verbose | normal | silent
+# Can be overridden with --silent or --log-level CLI flags
+# RUST_LOG env var takes absolute priority over all of these
+log_level = "normal"
 
 [general.modes]
 classic = false
@@ -39,14 +44,13 @@ client_ack = 300
 
 # === Anti-Censorship & Masking ===
 [censorship]
-tls_domain = "petrovich.ru"
+tls_domain = "google.ru"
 mask = true
 mask_port = 443
 # mask_host = "petrovich.ru" # Defaults to tls_domain if not set
 fake_cert_len = 2048
 
 # === Access Control & Users ===
-# username "hello" is used for example
 [access]
 replay_check_len = 65536
 replay_window_secs = 1800
@@ -63,17 +67,13 @@ hello = "00000000000000000000000000000000"
 # hello = 1073741824 # 1 GB
 
 # === Upstreams & Routing ===
-# By default, direct connection is used, but you can add SOCKS proxy
-
-# Direct - Default
 [[upstreams]]
 type = "direct"
 enabled = true
 weight = 10
 
-# SOCKS5
 # [[upstreams]]
 # type = "socks5"
 # address = "127.0.0.1:9050"
 # enabled = false
-# weight = 1
+# weight = 1