fix(readme): fetch README from jsDelivr to avoid npm registry truncation

The npm registry truncates the packument readme field at exactly
65,536 characters, causing large READMEs to render incomplete.

Fetch the actual README file from jsDelivr CDN (npm tarball) as the
primary source, falling back to the packument field when jsDelivr
doesn't have it.

Closes #1458

Author: lukeocodes

server/api/registry/readme/[...pkg].get.ts

@@ -17,9 +17,6 @@ const standardReadmeFilenames = [
   'readme.markdown',
 ]
 
-/** Matches standard README filenames (case-insensitive, for checking registry metadata) */
-const standardReadmePattern = /^readme(?:\.md|\.markdown)?$/i
-
 /**
  * Fetch README from jsdelivr CDN for a specific package version.
  * Falls back through common README filenames.
@@ -71,42 +68,25 @@ export default defineCachedEventHandler(
       })
 
       const packageData = await fetchNpmPackage(packageName)
-
-      let readmeContent: string | undefined
-      let readmeFilename: string | undefined
-
-      // If a specific version is requested, get README from that version
-      if (version) {
-        const versionData = packageData.versions[version]
-        if (versionData) {
-          readmeContent = versionData.readme
-          readmeFilename = versionData.readmeFilename
+      const resolvedVersion = version ?? packageData['dist-tags']?.latest
+
+      // Prefer jsDelivr (actual file from npm tarball) over the packument readme field,
+      // because the npm registry truncates readme content at 65,536 characters.
+      let readmeContent = await fetchReadmeFromJsdelivr(
+        packageName,
+        standardReadmeFilenames,
+        resolvedVersion,
+      )
+
+      // Fall back to packument readme if jsDelivr didn't have it
+      if (!readmeContent) {
+        const packumentReadme = version ? packageData.versions[version]?.readme : packageData.readme
+        if (packumentReadme && packumentReadme !== NPM_MISSING_README_SENTINEL) {
+          readmeContent = packumentReadme
         }
-      } else {
-        // Use the packument-level readme (from latest version)
-        readmeContent = packageData.readme
-        readmeFilename = packageData.readmeFilename
       }
 
-      const hasValidNpmReadme = readmeContent && readmeContent !== NPM_MISSING_README_SENTINEL
-
-      // If no README in packument, or if readmeFilename is non-standard (e.g., README.zh-TW.md),
-      // try fetching a standard README from jsdelivr (package tarball).
-      // Note: When readmeFilename is missing, we defensively fetch from jsdelivr to ensure
-      // we get a standard English README if one exists.
-      if (!hasValidNpmReadme || !isStandardReadme(readmeFilename)) {
-        const jsdelivrReadme = await fetchReadmeFromJsdelivr(
-          packageName,
-          standardReadmeFilenames,
-          version,
-        )
-        // Only replace npm content if jsdelivr returned something
-        if (jsdelivrReadme) {
-          readmeContent = jsdelivrReadme
-        }
-      }
-
-      if (!readmeContent || readmeContent === NPM_MISSING_README_SENTINEL) {
+      if (!readmeContent) {
         return { html: '', playgroundLinks: [], toc: [] }
       }
 
@@ -130,7 +110,3 @@ export default defineCachedEventHandler(
     },
   },
 )
-
-function isStandardReadme(filename: string | undefined): boolean {
-  return !!filename && standardReadmePattern.test(filename)
-}