Add provider fallback, visual schema builder, and UI improvements

Provider fallback system:
- Add optional fallback field to Provider dataclass
- Automatically try fallback provider when primary fails (timeout, error, offline)
- Prevent infinite loops with circular fallback detection
- Add fallback column and dropdown in providers UI

Visual schema builder for prompt steps:
- Add SchemaBuilderDialog with table-based field editor
- Support field name, type, description, and required flag
- Live JSON schema preview
- Integrate into PromptStepDialog with Edit Schema button
- Fix output_schema being lost when editing prompt steps

Other improvements:
- Add search box to tools page
- Improve schema example generation for structured output
- Update CLAUDE.md documentation

Co-Authored-By: Claude Opus 4.5 <[email protected]>

src/cmdforge/gui/pages/tools_page.py

@@ -9,7 +9,7 @@ import yaml
 from PySide6.QtWidgets import (
     QWidget, QVBoxLayout, QHBoxLayout, QSplitter,
     QTreeWidget, QTreeWidgetItem, QTextEdit, QLabel,
-    QPushButton, QGroupBox, QMessageBox, QFrame
+    QPushButton, QGroupBox, QMessageBox, QFrame, QLineEdit
 )
 from PySide6.QtCore import Qt, QThread, Signal, QTimer
 from PySide6.QtGui import QFont, QColor, QBrush, QShortcut, QKeySequence
@@ -402,6 +402,13 @@ class ToolsPage(QWidget):
         left_layout.setContentsMargins(0, 0, 0, 0)
         left_layout.setSpacing(8)
 
+        # Search box
+        self.search_box = QLineEdit()
+        self.search_box.setPlaceholderText("Search tools...")
+        self.search_box.setClearButtonEnabled(True)
+        self.search_box.textChanged.connect(self._filter_tools)
+        left_layout.addWidget(self.search_box)
+
         self.tool_tree = QTreeWidget()
         self.tool_tree.setHeaderHidden(True)
         self.tool_tree.setIndentation(16)
@@ -555,6 +562,7 @@ class ToolsPage(QWidget):
 
     def refresh(self):
         """Refresh the tool list."""
+        self.search_box.clear()
         self.tool_tree.clear()
         self._current_tool = None
         self.info_text.clear()
@@ -741,6 +749,43 @@ class ToolsPage(QWidget):
         self.refresh()
         self.main_window.show_status(f"Status updated for '{tool_name}'")
 
+    def _filter_tools(self, text: str):
+        """Filter tools by name or description based on search text."""
+        search = text.lower().strip()
+
+        for i in range(self.tool_tree.topLevelItemCount()):
+            category_item = self.tool_tree.topLevelItem(i)
+            visible_children = 0
+
+            for j in range(category_item.childCount()):
+                tool_item = category_item.child(j)
+                tool_name = tool_item.data(0, Qt.UserRole)
+
+                if not search:
+                    # No filter - show all
+                    tool_item.setHidden(False)
+                    visible_children += 1
+                else:
+                    # Check if name matches
+                    matches = search in tool_name.lower()
+
+                    # Also check description if we have the tool loaded
+                    if not matches:
+                        tool = load_tool(tool_name)
+                        if tool and tool.description:
+                            matches = search in tool.description.lower()
+
+                    tool_item.setHidden(not matches)
+                    if matches:
+                        visible_children += 1
+
+            # Hide category if no children match
+            category_item.setHidden(visible_children == 0)
+
+            # Expand categories when filtering to show results
+            if search and visible_children > 0:
+                category_item.setExpanded(True)
+
     def _on_selection_changed(self):
         """Handle tool selection change."""
         items = self.tool_tree.selectedItems()