feat: pantry drag-to-recategorize, always-show categories, auto-categorize; fix category label + merge quantity mismatch (v0.84.0)

Pantry items can now be dragged between category sections (dnd-kit, cross-category drop only — no sortOrder column to persist within-category reorder). All 9 categories always render as sections, even empty ones, instead of only ones with items. Added an "Auto-categorize" action mirroring the shopping list's guessAisle heuristic.

Fixed: the edit dialog's category dropdown displayed the raw stored slug/"__other__" instead of its translated label (SelectValue needs a value->label render function, same pattern shopping-list-view.tsx already used elsewhere). Fixed: merge-duplicates now merges by ingredient identity alone, not identity+unit — two rows merge even with mismatched, missing, or different-unit quantities, only summing when safe to do so.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

apps/web/messages/en.json

@@ -1182,7 +1182,8 @@
     "mergeDuplicates": "Merge duplicates",
     "mergeDuplicatesFailed": "Failed to merge duplicates",
     "mergeDuplicatesNoneFound": "No duplicates found",
-    "mergeDuplicatesSuccess": "{count, plural, one {Merged 1 duplicate item} other {Merged {count} duplicate items}}"
+    "mergeDuplicatesSuccess": "{count, plural, one {Merged 1 duplicate item} other {Merged {count} duplicate items}}",
+    "categoryEmptyDropHint": "Drag an item here to move it into this category."
   },
   "feed": {
     "title": "Feed",