chore: make the root tsconfig a self-contained editor project

The root config had no include, so the editor program for any src file
swallowed every file importing 'vitepress' (tests, docs configs) and with
them dist/node/index.d.ts — whose bundled copies of the vite and
default-theme augmentations collide with the source ones under different
type identities (TS2717), alongside ~1200 phantom errors from test
globals. The root project now covers only the sources and resolves
'vitepress' onto src the way tsconfig.client.json already does; every
other config extends tsconfig.base.json directly (the root added nothing
over it), leaving their programs byte-identical.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

__tests__/tsconfig.json

@@ -1,5 +1,5 @@
 {
-  "extends": "../tsconfig.json",
+  "extends": "../tsconfig.base.json",
   "compilerOptions": {
     "noEmit": true,
     "isolatedModules": false,

docs/tsconfig.json

@@ -1,5 +1,5 @@
 {
-  "extends": "../tsconfig.json",
+  "extends": "../tsconfig.base.json",
   "compilerOptions": {
     "allowImportingTsExtensions": true,
     "noEmit": true,

tsconfig.client.json

@@ -1,5 +1,5 @@
 {
-  "extends": "./tsconfig.json",
+  "extends": "./tsconfig.base.json",
   "compilerOptions": {
     "lib": ["ES2023", "DOM", "DOM.Iterable"],
     "types": ["./client.d.ts"],

tsconfig.json

@@ -1,3 +1,24 @@
+// the editor's project for the sources. Self-contained: `vitepress` resolves
+// onto src (same trick as tsconfig.client.json), so the built dist — whose
+// bundled types re-declare the `vite` and default-theme augmentations under
+// different type identities — never enters this program. Tests and docs have
+// their own nearest tsconfigs and resolve the package normally.
 {
-  "extends": "./tsconfig.base.json"
+  "extends": "./tsconfig.base.json",
+  "compilerOptions": {
+    "paths": {
+      "vitepress": ["./src/client/index.ts"],
+      "vitepress/theme": ["./types/default-theme.d.ts"],
+      "@siteData": ["./src/client/shims.d.ts"],
+      "@theme/index": ["./src/client/shims.d.ts"],
+      "@localSearchIndex": ["./src/client/shims.d.ts"]
+    }
+  },
+  "include": [
+    "src",
+    "types",
+    "scripts",
+    "shared-globals.d.ts",
+    "tsdown.config.ts"
+  ]
 }

tsconfig.node.json

@@ -1,5 +1,5 @@
 {
-  "extends": "./tsconfig.json",
+  "extends": "./tsconfig.base.json",
   "compilerOptions": {
     "lib": ["ES2023"],
     "types": ["node"]

tsconfig.shared.json

@@ -1,5 +1,5 @@
 {
-  "extends": "./tsconfig.json",
+  "extends": "./tsconfig.base.json",
   "compilerOptions": {
     "lib": ["ES2023"],
     "types": [],