Refactor and enhance security in proxy and handshake modules

- Updated `direct_relay_security_tests.rs` to ensure sanitized paths are correctly validated against resolved paths.
- Added tests for symlink handling in `unknown_dc_log_path_revalidation` to prevent symlink target escape vulnerabilities.
- Modified `handshake.rs` to use a more robust hashing strategy for eviction offsets, improving the eviction logic in `auth_probe_record_failure_with_state`.
- Introduced new tests in `handshake_security_tests.rs` to validate eviction logic under various conditions, ensuring low fail streak entries are prioritized for eviction.
- Simplified `route_mode.rs` by removing unnecessary atomic mode tracking, streamlining the transition logic in `RouteRuntimeController`.
- Enhanced `route_mode_security_tests.rs` with comprehensive tests for mode transitions and their effects on session states, ensuring consistency under concurrent modifications.
- Cleaned up `emulator.rs` by removing unused ALPN extension handling, improving code clarity and maintainability.

Cargo.lock

@@ -425,6 +425,32 @@ dependencies = [
  "cipher",
 ]
 
+[[package]]
+name = "curve25519-dalek"
+version = "4.1.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "97fb8b7c4503de7d6ae7b42ab72a5a59857b4c937ec27a3d4539dba95b5ab2be"
+dependencies = [
+ "cfg-if",
+ "cpufeatures",
+ "curve25519-dalek-derive",
+ "fiat-crypto",
+ "rustc_version",
+ "subtle",
+ "zeroize",
+]
+
+[[package]]
+name = "curve25519-dalek-derive"
+version = "0.1.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f46882e17999c6cc590af592290432be3bce0428cb0d5f8b6715e4dc7b383eb3"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn 2.0.114",
+]
+
 [[package]]
 name = "dashmap"
 version = "5.5.3"
@@ -517,6 +543,12 @@ version = "2.3.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "37909eebbb50d72f9059c3b6d82c0463f2ff062c9e95845c43a6c9c0355411be"
 
+[[package]]
+name = "fiat-crypto"
+version = "0.2.9"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "28dea519a9695b9977216879a3ebfddf92f1c08c05d984f8996aecd6ecdc811d"
+
 [[package]]
 name = "filetime"
 version = "0.2.27"
@@ -1609,7 +1641,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "6db2770f06117d490610c7488547d543617b21bfa07796d7a12f6f1bd53850d1"
 dependencies = [
  "rand_chacha",
- "rand_core",
+ "rand_core 0.9.5",
 ]
 
 [[package]]
@@ -1619,9 +1651,15 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "d3022b5f1df60f26e1ffddd6c66e8aa15de382ae63b3a0c1bfc0e4d3e3f325cb"
 dependencies = [
  "ppv-lite86",
- "rand_core",
+ "rand_core 0.9.5",
 ]
 
+[[package]]
+name = "rand_core"
+version = "0.6.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ec0be4795e2f6a28069bec0b5ff3e2ac9bafc99e6a9a7dc3547996c5c816922c"
+
 [[package]]
 name = "rand_core"
 version = "0.9.5"
@@ -1637,7 +1675,7 @@ version = "0.4.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "513962919efc330f829edb2535844d1b912b0fbe2ca165d613e4e8788bb05a5a"
 dependencies = [
- "rand_core",
+ "rand_core 0.9.5",
 ]
 
 [[package]]
@@ -2145,6 +2183,7 @@ dependencies = [
  "tracing-subscriber",
  "url",
  "webpki-roots 0.26.11",
+ "x25519-dalek",
  "x509-parser",
  "zeroize",
 ]
@@ -3144,6 +3183,18 @@ version = "0.6.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "9edde0db4769d2dc68579893f2306b26c6ecfbe0ef499b013d731b7b9247e0b9"
 
+[[package]]
+name = "x25519-dalek"
+version = "2.0.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c7e468321c81fb07fa7f4c636c3972b9100f0346e5b6a9f2bd0603a52f7ed277"
+dependencies = [
+ "curve25519-dalek",
+ "rand_core 0.6.4",
+ "serde",
+ "zeroize",
+]
+
 [[package]]
 name = "x509-parser"
 version = "0.15.1"