feat: Add bulk recategorization from Category and Group aggregate views

Implemented bulk recategorization feature for aggregate views, matching
the existing bulk merchant edit functionality.

**New Feature:**
- Press 'r' in Category view → recategorize all transactions in that category
- Press 'r' in Group view → recategorize all transactions in that group
- Shows category picker modal
- Queues edits for all transactions in the selected category/group

**Use Cases:**
1. **Category View**: Recategorize all "Miscellaneous" to "Groceries"
2. **Group View**: Move all "Uncategorized" group transactions to specific categories

**Workflow Example:**
```
1. View Categories (press 'c' or cycle with 'g')
2. Navigate to "Miscellaneous" category
3. Press 'r' to bulk recategorize
4. Type "groc" to filter, select "Groceries"
5. All Miscellaneous transactions queued for recategorization
6. Press 'w' to review and commit
```

**Implementation:**
- Added _bulk_recategorize_from_aggregate() method
- Handles both CATEGORY and GROUP views
- Similar pattern to _bulk_edit_merchant_from_aggregate()
- Shows clear notification with count and old→new category names

**UI Updates:**
- Action hints now show "r=Recategorize (bulk)" in Category/Group views
- Consistent with merchant bulk edit ("m=Edit merchant (bulk)")

**Benefits:**
- Quickly fix miscategorized transactions
- Power user workflow for bulk cleanup
- Same consistent pattern as bulk merchant edits

All 465 tests passing, pyright clean.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

Author: wesm

moneyflow/app.py

@@ -833,7 +833,10 @@ def update_action_hints(self) -> None:
             hints = (
                 f"Enter=Drill down | m=Edit merchant (bulk) | s=Sort({sort_name}) | g=Change grouping | ←/→=Change period"
             )
-        elif self.state.view_mode in [ViewMode.CATEGORY, ViewMode.GROUP, ViewMode.ACCOUNT]:
+        elif self.state.view_mode in [ViewMode.CATEGORY, ViewMode.GROUP]:
+            sort_name = self.state.sort_by.value.capitalize()
+            hints = f"Enter=Drill down | r=Recategorize (bulk) | s=Sort({sort_name}) | g=Change grouping | ←/→=Change period"
+        elif self.state.view_mode == ViewMode.ACCOUNT:
             sort_name = self.state.sort_by.value.capitalize()
             hints = f"Enter=Drill down | s=Sort({sort_name}) | g=Change grouping | ←/→=Change period"
         else:  # DETAIL (transactions)
@@ -1319,14 +1322,112 @@ async def _edit_merchant_detail(self) -> None:
                     table.move_cursor(row=saved_cursor_row)
 
     def action_recategorize(self) -> None:
-        """Change category for current selection."""
+        """Change category for current selection (works in aggregate and detail views)."""
         if self.data_manager is None:
             return
 
-        self.run_worker(self._recategorize(), exclusive=False)
+        # Check if in aggregate view (CATEGORY or GROUP) or detail view
+        if self.state.view_mode in [ViewMode.CATEGORY, ViewMode.GROUP]:
+            # Aggregate view - recategorize all transactions for this category/group
+            self.run_worker(self._bulk_recategorize_from_aggregate(), exclusive=False)
+        else:
+            # Detail view - recategorize selected transaction(s)
+            self.run_worker(self._recategorize(), exclusive=False)
+
+    async def _bulk_recategorize_from_aggregate(self) -> None:
+        """Recategorize all transactions in selected category/group."""
+        from .screens.edit_screens import SelectCategoryScreen
+
+        if self.state.current_data is None:
+            return
+
+        table = self.query_one("#data-table", DataTable)
+        if table.cursor_row < 0:
+            return
+
+        # Get the category/group from current row
+        row_data = self.state.current_data.row(table.cursor_row, named=True)
+
+        if self.state.view_mode == ViewMode.CATEGORY:
+            category_name = row_data["category"]
+            category_id = row_data["category_id"]
+            transaction_count = row_data["count"]
+            total_amount = row_data["total"]
+
+            # Show category selection
+            new_category_id = await self.push_screen(
+                SelectCategoryScreen(
+                    self.data_manager.categories,
+                    category_id,
+                    None  # No transaction details for bulk
+                ),
+                wait_for_dismiss=True,
+            )
+
+            if new_category_id and new_category_id != category_id:
+                # Get all transactions for this category
+                filtered_df = self.state.get_filtered_df()
+                category_txns = self.data_manager.filter_by_category(filtered_df, category_name)
+
+                # Add edits for all transactions
+                for txn in category_txns.iter_rows(named=True):
+                    self.data_manager.pending_edits.append(
+                        TransactionEdit(
+                            transaction_id=txn["id"],
+                            field="category",
+                            old_value=category_id,
+                            new_value=new_category_id,
+                            timestamp=datetime.now(),
+                        )
+                    )
+
+                new_cat_name = self.data_manager.categories.get(new_category_id, {}).get("name", "Unknown")
+                self.notify(
+                    f"Queued {len(category_txns)} transactions to recategorize: {category_name} → {new_cat_name}. Press w to commit.",
+                    timeout=3
+                )
+                self.refresh_view()
+        elif self.state.view_mode == ViewMode.GROUP:
+            group_name = row_data["group"]
+            transaction_count = row_data["count"]
+
+            # For group view, show category picker
+            # (groups don't have IDs, so we pick a category from that group)
+            new_category_id = await self.push_screen(
+                SelectCategoryScreen(
+                    self.data_manager.categories,
+                    None,  # No current category
+                    None  # No transaction details
+                ),
+                wait_for_dismiss=True,
+            )
+
+            if new_category_id:
+                # Get all transactions for this group
+                filtered_df = self.state.get_filtered_df()
+                group_txns = self.data_manager.filter_by_group(filtered_df, group_name)
+
+                # Add edits for all transactions
+                for txn in group_txns.iter_rows(named=True):
+                    self.data_manager.pending_edits.append(
+                        TransactionEdit(
+                            transaction_id=txn["id"],
+                            field="category",
+                            old_value=txn["category_id"],
+                            new_value=new_category_id,
+                            timestamp=datetime.now(),
+                        )
+                    )
+
+                new_cat_name = self.data_manager.categories.get(new_category_id, {}).get("name", "Unknown")
+                self.notify(
+                    f"Queued {len(group_txns)} transactions from {group_name} to recategorize to {new_cat_name}. Press w to commit.",
+                    timeout=3
+                )
+                self.refresh_view()
 
     async def _recategorize(self) -> None:
-        """Show category selection and apply."""
+        """Show category selection and apply (for detail view)."""
         from .screens.edit_screens import SelectCategoryScreen
         from .state import TransactionEdit