fix: truncate webfetch content to fit context

Plugins/ZShell/Llm/tool.cpp

@@ -6,6 +6,20 @@ LlmTool::LlmTool(QObject* parent) : QObject(parent) {}
 
 LlmTool::~LlmTool() = default;
 
+void LlmTool::setContextSize(int value) {
+	if (m_contextSize == value) return;
+	m_contextSize = value;
+}
+
+int LlmTool::inlineBudgetChars() const {
+	if (m_contextSize <= 0) return DefaultInlineChars;
+	// About a quarter of the context window, clamped so tiny contexts
+	// still get a usable result and huge ones stay sane.
+	const int tokens =
+		qBound(512, m_contextSize / 4, DefaultInlineChars / CharsPerToken);
+	return tokens * CharsPerToken;
+}
+
 void LlmTool::cancel() {}
 
 QJsonObject LlmTool::specification() const {
@@ -30,6 +44,7 @@ void ToolRegistry::setEnabled(bool value) {
 void ToolRegistry::registerTool(LlmTool* tool) {
 	if (!tool || m_tools.contains(tool)) return;
 	tool->setParent(this);
+	tool->setContextSize(m_contextSize);
 	m_tools.append(tool);
 }
 
@@ -52,4 +67,11 @@ void ToolRegistry::cancelAll() {
 		tool->cancel();
 }
 
+void ToolRegistry::setContextSize(int value) {
+	if (m_contextSize == value) return;
+	m_contextSize = value;
+	for (auto* tool : m_tools)
+		tool->setContextSize(value);
+}
+
 } // namespace ZShell::llm