chore(#1055): address argus review nits

- rename cap-cap-col → cap-col; add CSS rules for .cap-col and .cap-save-col
- drop zero-width-space replace in capability header cells (nowrap makes it a no-op)
- add Capability::ALL to hive-sh4re; validate incoming cap strings in post_capabilities

hive-c0re/src/dashboard.rs

@@ -2595,6 +2595,12 @@ async fn post_capabilities(
     if let Some(reject) = guard_agent_name(&state, &logical).await {
         return reject;
     }
+    let known: Vec<&str> = hive_sh4re::Capability::ALL.iter().map(|c| c.as_str()).collect();
+    for cap in &body.caps {
+        if !known.contains(&cap.as_str()) {
+            return error_response(&format!("unknown capability: {cap}"));
+        }
+    }
     if let Err(e) = crate::capabilities::set_caps(&logical, &body.caps) {
         return error_response(&format!("set capabilities for {logical}: {e}"));
     }