feat(dashboard): remove the SYST3M tab now that C0R3 owns it

Folds the SYST3M-tab removal into the same change that adds /core.html
(per operator review — it should be one PR, not an additive page + a
follow-up). Drops the tab + pane from dashboard.html and ~600 lines of
now-dead renderers/wiring from tabs.js: renderMetaInputs, renderRebuildQueue
+ renderQueueEntry + the rebuild-queue row cache / glyph maps / fingerprint,
renderTombstones, the container-load poll (cload* + start/stopContainerLoadPolling),
the two rqe-* elapsed tickers, the meta/tombstone state + sync + apply
handlers, their SSE dispatch entries, and the SYST3M tab-count.

Deliberately KEPT in tabs.js: rebuildQueueState + syncRebuildQueueFromSnapshot
+ applyRebuildQueueChanged + inFlightOpsByAgent — these don't render the
SYST3M panel, they drive the "building…" / "meta-updating…" badges on the
SW4RM agent cards, so the dashboard still subscribes to rebuild_queue_changed
to refresh those badges (applyRebuildQueueChanged now only re-renders
containers, no panel render).

core.css still imports dashboard.css for the shared section styles; splitting
those out + de-duping the renderers into a shared module remains a follow-up.

frontend/packages/dashboard/src/dashboard.html

@@ -35,12 +35,11 @@
         <span class="tab-label">◆ Y3R C4LL ◆</span>
         <span class="tab-count tab-count-attn" id="tab-count-call" hidden></span>
       </a>
-      <a class="tab" id="tab-system" href="#system" role="tab"
-         aria-controls="tab-pane-system"
-         data-tab="system">
-        <span class="tab-label">◆ SYST3M ◆</span>
-        <span class="tab-count" id="tab-count-system" hidden></span>
-      </a>
+      <!-- SYST3M moved to its own standalone page (/core.html, "C0R3"),
+           reached from the H0M3 hub — keeps the dashboard tab strip lean.
+           The rebuild-queue STATE still lives in tabs.js (it drives the
+           "building…" badges on SW4RM agent cards); only the SYST3M tab +
+           its section renderers moved out. -->
       <!-- P3RM1SS10NS: per-agent capability grants and tool-group
            assignments. Both tables are fetched on tab activation. -->
       <a class="tab" id="tab-permissions" href="#permissions" role="tab"
@@ -141,43 +140,9 @@
       </div>
     </section>
 
-    <!-- SYST3M: passive / rare-interaction state. Meta inputs (lock
-         bumps), rebuild queue (watch only), kept state from previous
-         tombstoned agents. Per-section content auto-compresses to a
-         one-line summary when empty (JS toggle). -->
-    <section class="tab-pane" id="tab-pane-system" data-tab-pane="system" hidden
-             role="tabpanel" aria-labelledby="tab-system">
-      <h2>◆ M3T4 1NPUTS ◆</h2>
-      <div class="divider">══════════════════════════════════════════════════════════════</div>
-      <p class="meta">select inputs to <code>nix flake update</code> in <code>/meta/</code>. selected agents rebuild in sequence after the lock bump; manager learns each outcome via the usual <code>rebuilt</code> system event.</p>
-      <div id="meta-inputs-section">
-        <p class="meta">loading…</p>
-      </div>
-
-      <h2>◆ R3BU1LD QU3U3 ◆</h2>
-      <div class="divider">══════════════════════════════════════════════════════════════</div>
-      <p class="meta">pending + running rebuilds, meta-updates, and first-spawns. one runs at a time; meta-update cascades nest under their parent. dedup: re-enqueueing a still-queued op collapses into the existing entry.</p>
-      <div id="rebuild-queue-section">
-        <p class="meta">loading…</p>
-      </div>
-
-      <h2>◆ K3PT ST4T3 ◆</h2>
-      <div class="divider">══════════════════════════════════════════════════════════════</div>
-      <div id="tombstones-section">
-        <p class="meta">loading…</p>
-      </div>
-
-      <!-- C0NT41N3R L04D: live cpu + memory per agent container, read
-           from cgroup v2 on the host. Polled only while this tab is
-           active (cpu needs a short two-sample read each refresh). -->
-      <h2>◆ C0NT41N3R L04D ◆</h2>
-      <div class="divider">══════════════════════════════════════════════════════════════</div>
-      <p class="meta">live cpu + memory per agent container, from cgroup v2 on the host. cpu is % of total host capacity (all cores), sampled over ~200ms each refresh; polled every 5s while this tab is open. network is omitted on purpose — agents share the host netns, so there is no per-container counter (see <code>docs/network.md</code>).</p>
-      <div id="container-load-section">
-        <p class="meta">loading…</p>
-      </div>
-
-    </section>
+    <!-- SYST3M pane moved to /core.html (the standalone "C0R3" page):
+         meta inputs, rebuild queue, kept state, container load. Reached
+         from the H0M3 hub. -->
 
     <!-- P3RM1SS10NS: per-agent capability grants + tool-group
          assignments. Both tables are column-driven from the backend