Mark @fedify/fixture as external in test build configs

During `pnpm pack --recursive`, tsdown tried to bundle @fedify/fixture
in the test build configs of several packages.  Since @fedify/fixture is
a private workspace package, its dist/ may not exist when parallel
prepack builds run, causing UNLOADABLE_DEPENDENCY errors.

Add "@fedify/fixture" to the external array in the test build config of:

 -  @fedify/webfinger
 -  @fedify/vocab
 -  @fedify/fedify
 -  @fedify/vocab-runtime

This aligns them with @fedify/testing, which already correctly
externalizes @fedify/fixture.

Co-authored-by: Amp (https://ampcode.com)
Amp-Thread-ID: https://ampcode.com/threads/T-019d00c0-4bd0-70fe-b81f-82e3738959e9
Co-authored-by: Amp <amp@ampcode.com>

Author: dahlia

packages/fedify/tsdown.config.ts

@@ -40,7 +40,7 @@ export default [
       ...(await Array.fromAsync(glob(`src/**/*.test.ts`)))
         .map((f) => f.replace(sep, "/")),
     ],
-    external: [/^node:/],
+    external: [/^node:/, "@fedify/fixture"],
     inputOptions: {
       onwarn(warning, defaultHandler) {
         if (

packages/vocab-runtime/tsdown.config.ts

@@ -16,6 +16,6 @@ export default [
       .map((f) => f.replace(sep, "/")),
     format: ["esm", "cjs"],
     platform: "node",
-    external: [/^node:/],
+    external: [/^node:/, "@fedify/fixture"],
   }),
 ];

packages/vocab/tsdown.config.ts

@@ -27,7 +27,7 @@ export default [
   defineConfig({
     entry: (await Array.fromAsync(glob(`src/**/*.test.ts`)))
       .map((f) => f.replace(sep, "/")),
-    external: [/^node:/],
+    external: [/^node:/, "@fedify/fixture"],
     inputOptions: {
       onwarn(warning, defaultHandler) {
         if (

packages/webfinger/tsdown.config.ts

@@ -15,6 +15,6 @@ export default [
       .map((f) => f.replace(sep, "/")),
     format: ["esm", "cjs"],
     platform: "node",
-    external: [/^node:/],
+    external: [/^node:/, "@fedify/fixture"],
   }),
 ];