fix: resolve TypeScript 6 typecheck issues

- Remove deprecated `downlevelIteration` from tsconfig.base.json (not needed for ES2022+ target)
- Add `noUncheckedSideEffectImports: false` to tsconfig.base.json and ckeditor5 package tsconfigs to allow CSS/plugin side-effect imports
- Remove deprecated `baseUrl: "."` from 6 package tsconfig.lib.json files (unused without `paths`)
- Replace `NodeJS.Timeout` with `ReturnType<typeof setTimeout>` in debounce.ts

Agent-Logs-Url: https://github.com/TriliumNext/Trilium/sessions/8e861e56-2be6-4c61-9558-a666abbe3ff0

Co-authored-by: eliandoran <21236836+eliandoran@users.noreply.github.com>

packages/ckeditor5-admonition/tsconfig.json

@@ -26,6 +26,7 @@
 	"moduleResolution": "NodeNext",
 	"module": "NodeNext",
 	"skipLibCheck": true,
+	"noUncheckedSideEffectImports": false,
 	"outDir": "out-tsc",
     "typeRoots": [
       "typings",

packages/ckeditor5-footnotes/tsconfig.json

@@ -26,6 +26,7 @@
 	"moduleResolution": "NodeNext",
 	"module": "NodeNext",
 	"skipLibCheck": true,
+	"noUncheckedSideEffectImports": false,
 	"outDir": "out-tsc",
     "typeRoots": [
       "typings",

packages/ckeditor5-keyboard-marker/tsconfig.json

@@ -26,6 +26,7 @@
 	"moduleResolution": "NodeNext",
 	"module": "NodeNext",
 	"skipLibCheck": true,
+	"noUncheckedSideEffectImports": false,
 	"outDir": "out-tsc",
     "typeRoots": [
       "typings",

packages/ckeditor5-math/tsconfig.json

@@ -26,6 +26,7 @@
 	"moduleResolution": "NodeNext",
 	"module": "NodeNext",
 	"skipLibCheck": true,
+	"noUncheckedSideEffectImports": false,
 	"outDir": "out-tsc",
     "typeRoots": [
       "typings",

packages/ckeditor5-mermaid/tsconfig.json

@@ -26,6 +26,7 @@
 	"moduleResolution": "NodeNext",
 	"module": "NodeNext",
 	"skipLibCheck": true,
+	"noUncheckedSideEffectImports": false,
 	"outDir": "out-tsc",
     "typeRoots": [
       "typings",

packages/ckeditor5/tsconfig.lib.json

@@ -3,7 +3,6 @@
   "compilerOptions": {
     "module": "ESNext",
     "moduleResolution": "bundler",
-    "baseUrl": ".",
     "rootDir": "src",
     "outDir": "dist",
     "tsBuildInfoFile": "dist/tsconfig.lib.tsbuildinfo",

packages/codemirror/tsconfig.lib.json

@@ -1,7 +1,6 @@
 {
   "extends": "../../tsconfig.base.json",
   "compilerOptions": {
-    "baseUrl": ".",
     "rootDir": "src",
     "outDir": "dist",
     "tsBuildInfoFile": "dist/tsconfig.lib.tsbuildinfo",

packages/commons/tsconfig.lib.json

@@ -1,7 +1,6 @@
 {
   "extends": "../../tsconfig.base.json",
   "compilerOptions": {
-    "baseUrl": ".",
     "rootDir": "src",
     "outDir": "dist",
     "tsBuildInfoFile": "dist/tsconfig.lib.tsbuildinfo",

packages/express-partial-content/tsconfig.lib.json

@@ -1,7 +1,6 @@
 {
   "extends": "../../tsconfig.base.json",
   "compilerOptions": {
-    "baseUrl": ".",
     "rootDir": "src",
     "outDir": "dist",
     "tsBuildInfoFile": "dist/tsconfig.lib.tsbuildinfo",

packages/highlightjs/tsconfig.lib.json

@@ -1,7 +1,6 @@
 {
   "extends": "../../tsconfig.base.json",
   "compilerOptions": {
-    "baseUrl": ".",
     "rootDir": "src",
     "outDir": "dist",
     "tsBuildInfoFile": "dist/tsconfig.lib.tsbuildinfo",

packages/share-theme/src/scripts/common/debounce.ts

@@ -1,5 +1,5 @@
 export default function debounce<T extends (...args: unknown[]) => unknown>(executor: T, delay: number) {
-    let timeout: NodeJS.Timeout | null;
+    let timeout: ReturnType<typeof setTimeout> | null;
     return function(...args: Parameters<T>): void {
         const callback = () => {
             timeout = null;

packages/turndown-plugin-gfm/tsconfig.lib.json

@@ -1,7 +1,6 @@
 {
   "extends": "../../tsconfig.base.json",
   "compilerOptions": {
-    "baseUrl": ".",
     "rootDir": "src",
     "outDir": "dist",
     "tsBuildInfoFile": "dist/tsconfig.lib.tsbuildinfo",

tsconfig.base.json

@@ -20,7 +20,7 @@
     "customConditions": ["development"],
     "verbatimModuleSyntax": false,  // TODO: Re-enable it when migrating back to ESM.
     "resolveJsonModule": true,
-    "downlevelIteration": true,
     "esModuleInterop": true,
+    "noUncheckedSideEffectImports": false,
   }
 }