feat: Show current category in recategorize modal

Added 'Current category:' label to SelectCategoryScreen to match
the 'Current merchant:' shown in EditMerchantScreen.

Makes both edit screens consistent in showing context.

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

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

Author: wesm

moneyflow/screens/edit_screens.py

@@ -342,6 +342,11 @@ def compose(self) -> ComposeResult:
                 )
                 yield Static(details_text, classes="edit-label")
 
+            # Show current category
+            if self.current_category_id and self.current_category_id in self.categories:
+                current_cat_name = self.categories[self.current_category_id]["name"]
+                yield Label(f"Current category: {current_cat_name}", classes="edit-label")
+
             yield Input(placeholder="Type to filter categories...", id="search-input")
 
             yield Static(f"{len(self.categories)} categories", id="results-count")