protobuff Process list

BREAKING: Process list over WS is now Protocol Buffers; client required.
Agent: returns all processes (no server-side top-k); large payloads gzip-compressed.
Client: decodes protobuf (gz/raw), moves sorting/pagination to TUI.
Build: add prost/prost-build with vendored protoc; enable thin LTO, panic=abort, strip symbols.
Cleanup: cfg-gate Linux-only code; fix Clippy across platforms; tests updated (ws probe TLS CA).

socktop_agent/build.rs

@@ -0,0 +1,11 @@
+fn main() {
+    // Ensure protoc exists (vendored for reproducible builds)
+    let protoc = protoc_bin_vendored::protoc_bin_path().expect("protoc");
+    std::env::set_var("PROTOC", protoc);
+
+    // Compile protobuf definitions for processes
+    let mut cfg = prost_build::Config::new();
+    cfg.out_dir(std::env::var("OUT_DIR").unwrap());
+    cfg.compile_protos(&["../proto/processes.proto"], &["../proto"])
+        .expect("compile protos");
+}