Add factory reset, safe catalog rebuild, and DB hardening

- Factory reset endpoint clears computed tables (catalog, nightly_cache,
  tonight, weather_cache), VACUUMs the DB, then rebuilds in background.
  Preserves all user data (imaging_log, gallery, phd2_logs, horizon).
- Catalog rebuild now fetches data BEFORE touching the DB — network
  failures no longer leave the catalog empty. DELETE + INSERT wrapped
  in a single transaction via replace_catalog() so a mid-write failure
  rolls back and old data is preserved.
- Added nightly_cache indexes and bumped pool to 10 connections with
  30s acquire timeout to prevent exhaustion during rebuilds.
- Settings page: factory reset button with inline confirmation dialog.

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

frontend/src/pages/Settings.tsx

@@ -285,6 +285,9 @@ export default function Settings() {
   const [recomputeMsg, setRecomputeMsg] = useState('');
   const [rebuilding, setRebuilding] = useState(false);
   const [rebuildResult, setRebuildResult] = useState<any>(null);
+  const [showResetConfirm, setShowResetConfirm] = useState(false);
+  const [resetting, setResetting] = useState(false);
+  const [resetMsg, setResetMsg] = useState('');
 
   const triggerRecompute = async () => {
     setRecomputing(true);
@@ -302,6 +305,26 @@ export default function Settings() {
     setRecomputing(false);
   };
 
+  const triggerFactoryReset = async () => {
+    setResetting(true);
+    setResetMsg('');
+    setShowResetConfirm(false);
+    try {
+      const res = await fetch('/api/factory-reset', { method: 'POST' });
+      if (res.ok) {
+        setResetMsg('Reset started. Catalog is rebuilding (~60s). Reload the page when done.');
+        qc.invalidateQueries({ queryKey: ['health'] });
+        qc.invalidateQueries({ queryKey: ['targets'] });
+      } else {
+        const d = await res.json().catch(() => ({}));
+        setResetMsg((d as { error?: string }).error ?? 'Backend returned an error.');
+      }
+    } catch {
+      setResetMsg('Error reaching backend.');
+    }
+    setResetting(false);
+  };
+
   const triggerRebuild = async () => {
     setRebuilding(true);
     setRebuildResult(null);
@@ -477,11 +500,82 @@ export default function Settings() {
               {recomputing ? 'Starting…' : 'Recompute Tonight'}
             </button>
           </div>
+
+          {/* Factory Reset */}
+          <div style={{ marginTop: 18, borderTop: '1px solid var(--border)', paddingTop: 14 }}>
+            {!showResetConfirm ? (
+              <button
+                onClick={() => setShowResetConfirm(true)}
+                disabled={resetting}
+                style={{
+                  padding: '6px 16px',
+                  background: 'rgba(224,82,82,0.1)',
+                  border: '1px solid rgba(224,82,82,0.4)',
+                  color: 'var(--danger)',
+                  borderRadius: 4,
+                  fontFamily: 'var(--font-mono)',
+                  fontSize: 12,
+                  cursor: resetting ? 'default' : 'pointer',
+                  opacity: resetting ? 0.6 : 1,
+                }}
+              >
+                {resetting ? 'Resetting…' : 'Factory Reset'}
+              </button>
+            ) : (
+              <div style={{ background: 'rgba(224,82,82,0.08)', border: '1px solid rgba(224,82,82,0.3)', borderRadius: 4, padding: '12px 14px' }}>
+                <div style={{ fontFamily: 'var(--font-mono)', fontSize: 12, color: 'var(--danger)', marginBottom: 8, fontWeight: 600 }}>
+                  Factory Reset
+                </div>
+                <div style={{ fontFamily: 'var(--font-mono)', fontSize: 11, color: 'var(--text-mid)', marginBottom: 10, lineHeight: 1.5 }}>
+                  Clears catalog, nightly cache, and weather data. Triggers a full rebuild (~60s).
+                  <br />
+                  <strong style={{ color: 'var(--text-hi)' }}>Imaging logs, gallery, PHD2 logs, and horizon are preserved.</strong>
+                </div>
+                <div style={{ display: 'flex', gap: 8 }}>
+                  <button
+                    onClick={triggerFactoryReset}
+                    style={{
+                      padding: '5px 14px',
+                      background: 'var(--danger)',
+                      color: '#fff',
+                      border: 'none',
+                      borderRadius: 3,
+                      fontFamily: 'var(--font-mono)',
+                      fontSize: 12,
+                      cursor: 'pointer',
+                    }}
+                  >
+                    Confirm Reset
+                  </button>
+                  <button
+                    onClick={() => setShowResetConfirm(false)}
+                    style={{
+                      padding: '5px 14px',
+                      background: 'var(--bg-deep)',
+                      border: '1px solid var(--border)',
+                      color: 'var(--text-mid)',
+                      borderRadius: 3,
+                      fontFamily: 'var(--font-mono)',
+                      fontSize: 12,
+                      cursor: 'pointer',
+                    }}
+                  >
+                    Cancel
+                  </button>
+                </div>
+              </div>
+            )}
+          </div>
           {recomputeMsg && (
             <div style={{ marginTop: 8, fontSize: 12, color: 'var(--text-mid)', fontFamily: 'var(--font-mono)' }}>
               {recomputeMsg}
             </div>
           )}
+          {resetMsg && (
+            <div style={{ marginTop: 8, fontSize: 12, color: resetting ? 'var(--text-mid)' : 'var(--good)', fontFamily: 'var(--font-mono)' }}>
+              {resetMsg}
+            </div>
+          )}
           {rebuildResult && (
             <div style={{ marginTop: 12, fontSize: 11, color: 'var(--text-mid)', fontFamily: 'var(--font-mono)', background: 'var(--bg-row)', padding: '10px 12px', borderRadius: 4 }}>
               {rebuildResult.error ? (