chore: version 1.51.0, path-dep the wasm examples, README notes

- socktop, socktop_agent, socktop_connector -> 1.51.0.
- socktop_wasm_test and zellij_socktop_plugin consume the in-repo
  connector via path deps so wasm-feature API drift is caught at PR time
  instead of after publish. Immediately proved out: the wasm requests
  module needed the new sampled_at_ms field, invisible to native builds.
- zellij plugin gains the standalone [workspace] marker (it could not be
  cargo-checked in-tree at all before). NOTE: its lib.rs has pre-existing
  compile errors unrelated to the connector (static mut STATE conflicts
  with register_plugin!, missing BTreeMap import) — needs its own rework,
  out of scope here.
- README: sampled_at_ms in the example payload.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

zellij_socktop_plugin/target/debug/build/rustversion-9c4be7ac1bc7d77a/invoked.timestamp

@@ -0,0 +1 @@
+This file has an mtime of when this was started.

zellij_socktop_plugin/target/debug/build/rustversion-9c4be7ac1bc7d77a/out/version.expr

@@ -0,0 +1,5 @@
+crate::version::Version {
+    minor: 96,
+    patch: 0,
+    channel: crate::version::Channel::Stable,
+}

zellij_socktop_plugin/target/debug/build/rustversion-9c4be7ac1bc7d77a/output

@@ -0,0 +1,3 @@
+cargo:rerun-if-changed=build/build.rs
+cargo:rustc-check-cfg=cfg(cfg_macro_not_allowed)
+cargo:rustc-check-cfg=cfg(host_os, values("windows"))

zellij_socktop_plugin/target/debug/build/rustversion-9c4be7ac1bc7d77a/root-output

@@ -0,0 +1 @@
+/home/jasonw/Documents/GitHub/socktop/zellij_socktop_plugin/target/debug/build/rustversion-9c4be7ac1bc7d77a/out