Feature/backend ts support andunification of auth settings on frontend

.gitignore

@@ -8,6 +8,7 @@ lerna-debug.log*
 
 # Build outputs
 dist/
+dist-server/
 dist-ssr/
 build/
 out/
@@ -138,4 +139,4 @@ tasks/
 !src/i18n/locales/de/tasks.json
 
 # Git worktrees
-.worktrees/
+.worktrees/

eslint.config.js

@@ -3,7 +3,9 @@ import tseslint from "typescript-eslint";
 import react from "eslint-plugin-react";
 import reactHooks from "eslint-plugin-react-hooks";
 import reactRefresh from "eslint-plugin-react-refresh";
-import importX from "eslint-plugin-import-x";
+import { createNodeResolver, importX } from "eslint-plugin-import-x";
+import { createTypeScriptImportResolver } from "eslint-import-resolver-typescript";
+import boundaries from "eslint-plugin-boundaries";
 import tailwindcss from "eslint-plugin-tailwindcss";
 import unusedImports from "eslint-plugin-unused-imports";
 import globals from "globals";
@@ -82,7 +84,7 @@ export default tseslint.config(
             "sibling",
             "index",
           ],
-          "newlines-between": "never",
+          "newlines-between": "always",
         },
       ],
 
@@ -98,5 +100,131 @@ export default tseslint.config(
       "no-control-regex": "off",
       "no-useless-escape": "off",
     },
+  },
+  {
+    files: ["server/**/*.{js,ts}"], // apply this block only to backend source files
+    ignores: ["server/**/*.d.ts"], // skip generated declaration files in backend linting
+    plugins: {
+      boundaries, // enforce backend architecture boundaries (module-to-module contracts)
+      "import-x": importX, // keep import hygiene rules (duplicates, unresolved paths, etc.)
+      "unused-imports": unusedImports, // remove dead imports/variables from backend files
+    },
+    languageOptions: {
+      parser: tseslint.parser, // parse both JS and TS syntax in backend files
+      parserOptions: {
+        ecmaVersion: "latest", // support modern ECMAScript syntax in backend code
+        sourceType: "module", // treat backend files as ESM modules
+      },
+      globals: {
+        ...globals.node, // expose Node.js globals such as process, Buffer, and __dirname equivalents
+      },
+    },
+    settings: {
+      "boundaries/include": ["server/**/*.{js,ts}"], // only analyze dependency boundaries inside backend files
+      "import/resolver": {
+        // boundaries resolves imports through eslint-module-utils, which reads the classic
+        // import/resolver setting instead of import-x/resolver-next.
+        typescript: {
+          project: ["server/tsconfig.json"], // resolve backend aliases using the canonical backend tsconfig
+          alwaysTryTypes: true, // keep normal TS package/type resolution working alongside aliases
+        },
+        node: {
+          extensions: [".mjs", ".cjs", ".js", ".json", ".node", ".ts", ".tsx"], // preserve Node-style fallback resolution for plain files
+        },
+      },
+      "import-x/resolver-next": [
+        // ESLint's import plugin does not read tsconfig path aliases on its own.
+        // This resolver teaches import-x how to understand the backend-only "@/*"
+        // mapping defined in server/tsconfig.json, which fixes false no-unresolved errors in editors.
+        createTypeScriptImportResolver({
+          project: ["server/tsconfig.json"], // point the resolver at the canonical backend tsconfig instead of the frontend one
+          alwaysTryTypes: true, // keep standard TypeScript package resolution working while backend aliases are enabled
+        }),
+        // Keep Node-style resolution available for normal package imports and plain relative JS files.
+        // The TypeScript resolver handles aliases, while the Node resolver preserves the expected fallback behavior.
+        createNodeResolver({
+          extensions: [".mjs", ".cjs", ".js", ".json", ".node", ".ts", ".tsx"],
+        }),
+      ],
+      "boundaries/elements": [
+        {
+          type: "backend-shared-types", // shared backend type contract that modules may consume without creating runtime coupling
+          pattern: ["server/shared/types.{js,ts}"], // support the current shared types path
+          mode: "file", // treat the types file itself as the boundary element instead of the whole folder
+        },
+        {
+          type: "backend-module", // logical element name used by boundaries rules below
+          pattern: "server/modules/*", // each direct folder in server/modules is treated as one module boundary
+          mode: "folder", // classify dependencies at folder-module level (not per individual file)
+          capture: ["moduleName"], // capture the module folder name for messages/debugging/template use
+        },
+      ],
+    },
+    rules: {
+      // --- Unused imports/vars (backend) ---
+      "unused-imports/no-unused-imports": "warn", // warn when imports are not used so they can be cleaned up
+      "unused-imports/no-unused-vars": "off", // keep backend signal focused on dead imports instead of local unused variables
+
+      // --- Import hygiene (backend) ---
+      "import-x/no-duplicates": "warn", // prevent duplicate import lines from the same module
+      "import-x/order": [
+        "warn", // keep backend import grouping/order consistent with the frontend config
+        {
+          groups: [
+            "builtin", // Node built-ins such as fs, path, and url come first
+            "external", // third-party packages come after built-ins
+            "internal", // aliased internal imports such as @/... come next
+            "parent", // ../ imports come after aliased internal imports
+            "sibling", // ./foo imports come after parent imports
+            "index", // bare ./ imports stay last
+          ],
+          "newlines-between": "always", // require a blank line between import groups in backend files too
+        },
+      ],
+      "import-x/no-unresolved": "error", // fail when an import path cannot be resolved
+      "import-x/no-useless-path-segments": "warn", // prefer cleaner paths (remove redundant ./ and ../ segments)
+      "import-x/no-absolute-path": "error", // disallow absolute filesystem imports in backend files
+
+      // --- General safety/style (backend) ---
+      eqeqeq: ["warn", "always", { null: "ignore" }], // avoid accidental coercion while still allowing x == null checks
+
+      // --- Architecture boundaries (backend modules) ---
+      "boundaries/dependencies": [
+        "error", // treat architecture violations as lint errors
+        {
+          default: "allow", // allow normal imports unless a rule below explicitly disallows them
+          checkInternals: false, // do not apply these cross-module rules to imports inside the same module
+          rules: [
+            {
+              from: { type: "backend-module" }, // modules may depend on the shared types contract only as erased type-only imports
+              to: { type: "backend-shared-types" },
+              disallow: {
+                dependency: { kind: ["value", "typeof"] },
+              }, // block runtime imports so shared types stay a compile-time contract instead of a hidden shared module
+              message:
+                "Backend modules may only use `import type` when importing from server/shared/types.ts (or server/types.ts).",
+            },
+            {
+              to: { type: "backend-module" }, // when importing anything that belongs to another backend module
+              disallow: { to: { internalPath: "**" } }, // block all direct/deep imports into module internals by default
+              message:
+                "Cross-module imports must go through that module's barrel file (server/modules/<module>/index.ts or index.js).", // explicit error message for architecture violations
+            },
+            {
+              to: { type: "backend-module" }, // same target scope as the disallow rule above
+              allow: {
+                to: {
+                  internalPath: [
+                    "index", // allow extensionless barrel imports resolved as module root index
+                    "index.{js,mjs,cjs,ts,tsx}", // allow explicit index.* barrel file imports
+                  ],
+                },
+              }, // re-allow only public module entry points (barrel files)
+            },
+          ],
+        },
+      ],
+      "boundaries/no-unknown": "error", // fail fast if boundaries cannot classify a dependency, which prevents silent rule bypasses
+    },
   }
 );