feat(#1098): replace deployed:hash chip with config link in three-dot menu

Remove the deployed sha plain-text badge from the card head.
Add a forge-linked menu item to the three-dot menu instead:
'deployed:abc123def012 ↗' opens agent-configs/<name>/commit/<sha>
on the hive forge in a new tab.

Only shown when both c.deployed_sha and forgeBase are present.
buildAgentMenu now takes forgeBase as second arg; call site passes
the same forgeBase computed for nav-strip links.

CSS: add text-decoration: none + box-sizing to .agent-menu-item
so <a> link items render identically to the <button> items.

frontend/packages/dashboard/src/dashboard.css

@@ -415,6 +415,8 @@ body.dashboard-shell {
   text-align: left;
   padding: 0.4em 0.9em;
   cursor: pointer;
+  text-decoration: none;
+  box-sizing: border-box;
 }
 .agent-menu-item:hover {
   background: var(--border);

frontend/packages/dashboard/src/tabs.js

@@ -381,7 +381,7 @@ window.marked = marked;
     }
   }
 
-  function buildAgentMenu(c) {
+  function buildAgentMenu(c, forgeBase) {
     const wrap = el('div', { class: 'agent-menu' });
     const btn = el('button', {
       type: 'button',
@@ -444,6 +444,20 @@ window.marked = marked;
       );
     }
 
+    if (c.deployed_sha && forgeBase) {
+      const li = el('li', { role: 'presentation' });
+      const a = el('a', {
+        class: 'agent-menu-item',
+        href: `${forgeBase}/agent-configs/${encodeURIComponent(c.name)}/commit/${c.deployed_sha}`,
+        target: '_blank',
+        rel: 'noopener',
+        role: 'menuitem',
+        title: 'deployed config commit on forge',
+      }, `deployed:${c.deployed_sha} ↗`);
+      li.append(a);
+      dropdown.append(menuSep(), li);
+    }
+
     btn.addEventListener('click', (e) => {
       e.stopPropagation();
       const wasHidden = dropdown.hidden;
@@ -779,11 +793,8 @@ window.marked = marked;
           {}, { noRefresh: true },
         ));
       }
-      if (c.deployed_sha) {
+
-        head.append(el('span',
+
-          { class: 'meta', title: 'sha currently locked in /meta/flake.lock' },
-          `deployed:${c.deployed_sha}`));
-      }
       if (c.pending_reminders && c.pending_reminders > 0) {
         head.append(el('span',
           {
@@ -838,7 +849,7 @@ window.marked = marked;
       // chip in the head row stays — it's a state-hint, not an
       // action button.
 
-      li.append(icon, body, buildAgentMenu(c));
+      li.append(icon, body, buildAgentMenu(c, forgeBase));
       ul.append(li);
     }
     root.append(ul);