swarm-ui: show an agent's details in a popover, not a modal dialog

The details open under the agent badge without dimming or blocking the page; a click outside or Escape closes it. New ui/popover primitive (anchored, portal, no backdrop) with a sample on the components page. A confirm or link dialog opened from inside it stays modal, and the popover ignores clicks and Escape that belong to that dialog. AgentDetailDialog becomes AgentDetailPopover.

frontend/packages/swarm-ui/src/pages/ComponentsPage.tsx

@@ -30,6 +30,7 @@ import {
 import { Button, type ButtonVariant } from "../ui/button/Button.js";
 import { Dialog } from "../ui/dialog/Dialog.js";
 import { ConfirmDialog } from "../ui/confirm-dialog/ConfirmDialog.js";
+import { Popover } from "../ui/popover/Popover.js";
 import { Badge, type BadgeTone } from "@hive/shared/badge.js";
 import { GearIcon } from "@hive/shared/icons.js";
 import { Dropdown, type DropdownOption } from "@hive/shared/dropdown.js";
@@ -231,6 +232,33 @@ function DialogSample() {
   );
 }
 
+// `Popover` anchors to the trigger it is given and toggles from it, so the
+// sample needs the trigger's ref and its own `open` state.
+function PopoverSample() {
+  const [open, setOpen] = useState(false);
+  const anchorRef = useRef<HTMLSpanElement>(null);
+  return (
+    <>
+      <span ref={anchorRef}>
+        <Button onClick={() => setOpen((o) => !o)}>toggle popover</Button>
+      </span>
+      <Popover
+        open={open}
+        onClose={() => setOpen(false)}
+        anchorRef={anchorRef}
+        label="sample popover"
+      >
+        <Panel title="a popover" icon="🔗" onClose={() => setOpen(false)}>
+          <p>
+            Floats under its trigger and leaves the page behind it clickable.
+            Outside click or Escape closes it.
+          </p>
+        </Panel>
+      </Popover>
+    </>
+  );
+}
+
 // `plain`: a `Panel`'s own header bar/border is the dialog's
 // only card, not a second one nested inside `Dialog`'s own — pair
 // `plain` with `Panel`'s `onClose` so the close button still exists,
@@ -511,6 +539,12 @@ export function ComponentsPage() {
         </Sample>
       </Section>
 
+      <Section title="Popover">
+        <Sample label="anchored, no backdrop, content supplies its own card">
+          <PopoverSample />
+        </Sample>
+      </Section>
+
       <Section title="ConfirmDialog">
         <Sample label="modal, cancel/confirm button row">
           <ConfirmDialogSample />