Wire up reactive signal updates to conditionals

Critical change that makes conditionals reactive:

- Added signal_conditional_deps map to track dependencies
- Added _extract_signals_from_expr() to find signals in expressions
- Populate dependency map during _collect_conditionals()
- Replace TODO comments in signal setters with reevaluate calls

How it works:
1. During collection, analyze if/match test/subject expressions
2. Extract all signal names referenced in conditions
3. Build map: signal_name -> [conditional_ids that use it]
4. When signal is updated (assign/augassign), call reevaluate for each dependent conditional

Example: set_tab_0() now:
  store i32 0, i32* @signal_Tabs_tab_index
  call void @reevaluate_conditional_4()
  call void @reevaluate_conditional_5()
  call void @reevaluate_conditional_6()
  call void @reevaluate_conditional_7()

This makes tabs fully interactive!

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

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

ritz/llvm_codegen_signals.py

@@ -37,6 +37,9 @@ class SignalLLVMIRGenerator:
         # Track signal-to-DOM bindings for updates
         self.signal_dom_bindings: dict[str, list[str]] = {}  # signal_name -> [dom_node_ids]
 
+        # Track signal-to-conditional dependencies for reactivity
+        self.signal_conditional_deps: dict[str, list[int]] = {}  # signal_name -> [conditional_ids]
+
         # Track current component for signal scoping
         self.current_component = None
 
@@ -67,6 +70,7 @@ class SignalLLVMIRGenerator:
             self.event_handlers = []
             self.conditionals = []
             self.conditional_map = {}
+            self.signal_conditional_deps = {}
 
             # Collect signals, handlers, and conditionals for this component
             self._collect_signals_and_handlers(component)
@@ -133,6 +137,44 @@ class SignalLLVMIRGenerator:
 
         scan_statements(component["body"])
 
+        # Build signal -> conditional dependency map
+        for cond_info in self.conditionals:
+            cond_id = cond_info["id"]
+            if cond_info["type"] == "if":
+                # Extract signals from test expression
+                signals = self._extract_signals_from_expr(cond_info["test"])
+            elif cond_info["type"] == "match":
+                # Extract signals from subject expression
+                signals = self._extract_signals_from_expr(cond_info["subject"])
+            else:
+                signals = []
+
+            # Register this conditional as dependent on these signals
+            for signal_name in signals:
+                if signal_name not in self.signal_conditional_deps:
+                    self.signal_conditional_deps[signal_name] = []
+                self.signal_conditional_deps[signal_name].append(cond_id)
+
+    def _extract_signals_from_expr(self, expr: dict[str, Any]) -> list[str]:
+        """Extract signal names referenced in an expression."""
+        signals = []
+
+        if expr["type"] == "name":
+            # Direct signal reference
+            signal_name = expr["id"]
+            if signal_name in self.signals:
+                signals.append(signal_name)
+        elif expr["type"] == "compare":
+            # Comparison expression - check left and right
+            signals.extend(self._extract_signals_from_expr(expr["left"]))
+            for comparator in expr.get("comparators", []):
+                signals.extend(self._extract_signals_from_expr(comparator))
+        elif expr["type"] == "constant":
+            # Constants don't reference signals
+            pass
+
+        return signals
+
     def _emit_header(self) -> None:
         """Emit module header."""
         self.lines.append("; Generated by Ritz Framework with Signals")
@@ -248,8 +290,10 @@ class SignalLLVMIRGenerator:
                 # Store the value
                 self.lines.append(f"  store i32 {value_var}, i32* {self._signal_global(signal_name)}")
 
-                # TODO: Trigger DOM updates
-                self.lines.append(f"  ; TODO: Update DOM nodes bound to {signal_name}")
+                # Trigger reactive updates for conditionals that depend on this signal
+                if signal_name in self.signal_conditional_deps:
+                    for cond_id in self.signal_conditional_deps[signal_name]:
+                        self.lines.append(f"  call void @reevaluate_conditional_{cond_id}()")
         elif stmt["type"] == "augassign":
             # Handle signal updates (count += 1)
             signal_name = stmt["target"]
@@ -267,8 +311,10 @@ class SignalLLVMIRGenerator:
                 # Store back
                 self.lines.append(f"  store i32 %{result_var}, i32* {self._signal_global(signal_name)}")
 
-                # TODO: Trigger DOM updates for this signal
-                self.lines.append(f"  ; TODO: Update DOM nodes bound to {signal_name}")
+                # Trigger reactive updates for conditionals that depend on this signal
+                if signal_name in self.signal_conditional_deps:
+                    for cond_id in self.signal_conditional_deps[signal_name]:
+                        self.lines.append(f"  call void @reevaluate_conditional_{cond_id}()")
 
     def _emit_conditional_functions(self) -> None:
         """Emit init and reevaluate functions for each conditional."""