feat: Add Tier 3-4 ZRTL plugins with async support

Tier 3 Plugins:
- zrtl_crypto: Hashing (SHA256/512, MD5), Base64, Hex, UUID v4/v7,
  cryptographically secure random using getrandom crate
- zrtl_http: Full HTTP client with request builder API, async support
  (get_async, post_async, request_send_async)
- zrtl_compress: Gzip/Zlib/Deflate compression using byte arrays

Tier 4 Plugins:
- zrtl_sql: SQLite database with handle-based API using rusqlite
- zrtl_websocket: WebSocket client with async support using tungstenite

Async Infrastructure:
- All I/O plugins now support ZrtlPromise-based async operations
- HTTP: http_get_async, http_post_async, http_request_send_async
- WebSocket: ws_connect_async, ws_recv_async, ws_send_async
- Network: net_tcp_connect_async, net_tcp_accept_async, net_tcp_read_async
- Thread-based futures with proper state machine cleanup
- Type-tagged promise states for correct memory deallocation

Improvements:
- zrtl_math: RNG now seeded with OS entropy via getrandom
- zrtl_crypto: Uses getrandom for cryptographically secure random
- All plugins have proper memory management and error handling

100 tests passing across 16 plugins.

Author: darmie

.DS_Store

@@ -12,6 +12,11 @@ members = [
     "zrtl_json",
     "zrtl_regex",
     "zrtl_process",
+    "zrtl_crypto",
+    "zrtl_http",
+    "zrtl_compress",
+    "zrtl_sql",
+    "zrtl_websocket",
 ]
 
 [workspace.dependencies]

plugins/Cargo.toml

@@ -0,0 +1,13 @@
+[package]
+name = "zrtl_compress"
+version = "0.1.0"
+edition = "2021"
+description = "ZRTL Compress plugin - gzip, zlib, and deflate compression"
+license = "Apache-2.0"
+
+[lib]
+crate-type = ["cdylib", "staticlib", "rlib"]
+
+[dependencies]
+zrtl = { path = "../../sdk/zrtl" }
+flate2 = "1.0"