Refactor runtime executor integration and introduce eino package

- Replaced the existing runtime executor with a new eino package for better modularity.
- Updated Service struct to use the new RuntimeExecutor from eino.
- Adjusted Run and Resume methods to accommodate changes in input types and execution logic.
- Introduced new types in the eino package to align with the previous executor's functionality.
- Refactored tooling preparation logic to streamline tool definitions and improve clarity.
- Added new context builders and event consumers to enhance runtime event handling.
- Removed legacy executor code and ensured all references are updated to the new eino package.

internal/ai/runtime/executor/helpers.go

@@ -0,0 +1,28 @@
+package executor
+
+import "strings"
+
+func appendIfMissing(items []string, item string) []string {
+	item = strings.TrimSpace(item)
+	if item == "" {
+		return items
+	}
+	for _, existing := range items {
+		if strings.TrimSpace(existing) == item {
+			return items
+		}
+	}
+	return append(items, item)
+}
+
+func preview(text string, limit int) string {
+	text = strings.TrimSpace(text)
+	if text == "" || limit <= 0 {
+		return ""
+	}
+	runes := []rune(text)
+	if len(runes) <= limit {
+		return string(runes)
+	}
+	return string(runes[:limit]) + "..."
+}