Fix six quality findings from iterative code review

- patch_ui.py: find_bundle now matches MARKER so already-patched files
  return early and print 'UI already patched' instead of the misleading
  'filterByProviders pattern not found' warning
- install.sh: scope warning grep to current run only (record log offset
  before apply.sh, tail -c +N to read only new bytes)
- install.sh: fix misleading 'before continuing' wording on warning banner
- install.sh: fix grep anchor (^WARNING: missed [truecloud-patch] WARNING: lines)
- uninstall.sh: add import-middlewared verification after Python detection,
  matching apply.sh fallback logic

install.sh

@@ -84,11 +84,16 @@ fi
 # ── Apply now ─────────────────────────────────────────────────────────────────
 
 echo "Applying patches ..."
+_log_start=$(wc -c < "$PATCH_DIR/apply.log" 2>/dev/null || echo 0)
 bash "$PATCH_DIR/apply.sh"
 echo ""
 echo "Patch log ($PATCH_DIR/apply.log):"
 tail -30 "$PATCH_DIR/apply.log"
 echo ""
+if tail -c "+$((_log_start + 1))" "$PATCH_DIR/apply.log" 2>/dev/null | grep -q "WARNING:"; then
+    echo "WARNING: apply.sh reported one or more issues — see log above for details."
+    echo ""
+fi
 
 # ── Restart middlewared ───────────────────────────────────────────────────────