dashboard: move infra container logs to dedicated INFRA tab

logs.html/logs.js previously showed infra containers (hive-ci, hive-forge,
hive-gateway, hive-matrix) in an optgroup within the AGENT tab selector.
This was confusing because infra containers don't run the per-agent hive
daemons, making the unit filter meaningless for them.

Changes:
- Add INFRA tab (between AGENT and SYSTEM) with its own container selector
  and full-machine-journal fetch (no unit filter).
- Remove the infra optgroup from the AGENT tab — it now shows agents only.
- loadContainerLists() replaces loadAgentList(): fetches /api/state once and
  populates both selectors, avoiding a duplicate network request.
- Deep-link (?agent=hive-ci) now routes to the INFRA tab when the named
  container is an infra container, falling back to AGENT otherwise.
- Remove syncUnitSelectForSelection() — no longer needed since the AGENT
  tab no longer contains infra containers.
- Extend the 30s timestamp ticker to cover the INFRA tab fetch time.

No backend changes: /api/journal/{name} already supports infra container names.

frontend/packages/dashboard/src/logs.html

@@ -15,8 +15,8 @@
   <!-- Minimal chrome: back link + sub-tab strip.
        Same pattern as flow.html — no full dashboard tabbar. Back link
        points to the H0M3 hub (served at /), not the dashboard.
-       Three sub-tabs: AGENT, SYSTEM, AUDIT. Build log history has moved
-       to /builds.html (the build lifecycle hub). -->
+       Four sub-tabs: AGENT, INFRA, SYSTEM, AUDIT. Build log history has
+       moved to /builds.html (the build lifecycle hub). -->
   <header class="page-header">
     <a class="page-back" href="/">← home</a>
     <nav class="hive-tabbar logs-tabbar" id="logs-tabbar" role="tablist">
@@ -24,6 +24,10 @@
          aria-controls="logs-pane-agent" data-tab="agent">
         <span class="logs-tab-label">AGENT</span>
       </a>
+      <a class="hive-tab" id="logs-tab-infra" href="#infra" role="tab"
+         aria-controls="logs-pane-infra" data-tab="infra">
+        <span class="logs-tab-label">INFRA</span>
+      </a>
       <a class="hive-tab" id="logs-tab-system" href="#system" role="tab"
          aria-controls="logs-pane-system" data-tab="system">
         <span class="logs-tab-label">SYSTEM</span>
@@ -57,6 +61,21 @@
       <pre id="agent-output" class="journal-output">select an agent above</pre>
     </section>
 
+    <!-- INFRA: journald viewer for infrastructure containers (hive-ci,
+         hive-forge, hive-gateway, hive-matrix). Always fetches the full
+         machine journal — no unit filter (infra containers don't run the
+         per-agent hive daemons). Backed by GET /api/journal/{name}?lines=N.
+         Deep-link: ?agent=hive-ci routes here instead of the AGENT tab. -->
+    <section class="logs-pane" id="logs-pane-infra" data-tab-pane="infra"
+             role="tabpanel" aria-labelledby="logs-tab-infra">
+      <div class="logs-toolbar">
+        <select id="infra-select" class="journal-unit"></select>
+        <button type="button" class="btn btn-restart" id="infra-refresh">↻ refresh</button>
+        <span id="infra-fetch-ts" class="meta logs-fetch-ts" hidden></span>
+      </div>
+      <pre id="infra-output" class="journal-output">select a container above</pre>
+    </section>
+
     <!-- SYSTEM: host-side service logs. Shows the hive-c0re daemon
          journal via GET /api/journal-host?unit=hive-c0re.service. -->
     <section class="logs-pane" id="logs-pane-system" data-tab-pane="system"