feat(admin): centralize tool & module settings in Werkzeuge tab with per-tool permissions, DB-backed config, connection tests, and cog-button navigation

frontend/src/types/toolConfig.types.ts

@@ -0,0 +1,12 @@
+export interface ToolConfig {
+  url: string;
+  tokenId?: string;      // bookstack only
+  tokenSecret?: string;  // bookstack only (masked — last 4 chars visible)
+  apiToken?: string;     // vikunja only (masked)
+}
+
+export interface ToolTestResult {
+  success: boolean;
+  message: string;
+  latencyMs: number;
+}