feat: jobs system with dedicated nav page and run history

Replaces ad-hoc Tailscale config tracking with a proper jobs system.
Jobs get their own nav page (master/detail layout), a dedicated DB
table, and full run history persisted forever. Tailscale connection
settings move from the Settings modal into the Jobs page. Registry
pattern makes adding future jobs straightforward.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

index.html

@@ -22,6 +22,7 @@
       <span class="nav-divider">·</span>
       <span id="nav-version"></span>
     </div>
+    <button class="nav-btn" onclick="navigate('jobs')">Jobs <span id="nav-jobs-dot" class="nav-job-dot nav-job-dot--none"></span></button>
     <button class="nav-btn" onclick="openSettingsModal()" title="Settings">&#9881;</button>
   </nav>
 
@@ -171,6 +172,19 @@
   </div>
 </div>
 
+<!-- JOBS PAGE -->
+<div class="page" id="page-jobs">
+  <div class="jobs-layout">
+    <div class="jobs-sidebar">
+      <div class="jobs-sidebar-title">Jobs</div>
+      <div id="jobs-list"></div>
+    </div>
+    <div class="jobs-detail" id="jobs-detail">
+      <div class="jobs-placeholder">Select a job</div>
+    </div>
+  </div>
+</div>
+
 <!-- SETTINGS MODAL -->
 <div id="settings-modal" class="modal-overlay">
   <div class="modal">
@@ -199,31 +213,6 @@
           <button class="btn btn-danger" onclick="importDB()">Import</button>
         </div>
       </div>
-      <div class="settings-section">
-        <div class="settings-section-title">Tailscale Sync</div>
-        <p class="settings-desc">Sync Tailscale status and IPs by matching device hostnames to instance names.</p>
-        <div class="settings-row" style="margin-bottom:12px">
-          <label class="settings-label" for="ts-enabled">Enable</label>
-          <input type="checkbox" id="ts-enabled" style="accent-color:var(--accent);width:14px;height:14px">
-        </div>
-        <div class="form-group">
-          <label class="form-label" for="ts-tailnet">Tailnet</label>
-          <input class="form-input" id="ts-tailnet" type="text" placeholder="e.g. Tt3Btpm6D921CNTRL">
-        </div>
-        <div class="form-group">
-          <label class="form-label" for="ts-api-key">API Key</label>
-          <input class="form-input" id="ts-api-key" type="password" placeholder="tskey-api-…">
-        </div>
-        <div class="form-group">
-          <label class="form-label" for="ts-poll">Poll Interval (minutes)</label>
-          <input class="form-input" id="ts-poll" type="number" min="1" placeholder="15">
-        </div>
-        <div class="settings-row" style="gap:8px;margin-bottom:8px">
-          <button class="btn btn-secondary" onclick="saveTailscaleSettings()">Save</button>
-          <button class="btn btn-secondary" id="ts-run-btn" onclick="runTailscaleNow()">Run Now</button>
-        </div>
-        <div id="ts-status" class="settings-desc" style="margin:4px 0 0;color:var(--text3)">—</div>
-      </div>
     </div>
   </div>
 </div>