refactor(shared): consolidate plugin entry migration and detection utilities

src/shared/log-legacy-plugin-startup-warning.ts

@@ -1,20 +1,9 @@
 import { checkForLegacyPluginEntry } from "./legacy-plugin-warning"
 import { log } from "./logger"
-import { migrateLegacyPluginEntry } from "./plugin-entry-migrator"
+import { migrateLegacyPluginEntry } from "./migrate-legacy-plugin-entry"
+import { toCanonicalEntry } from "./plugin-entry-migrator"
 import { LEGACY_PLUGIN_NAME, PLUGIN_NAME } from "./plugin-identity"
 
-function toCanonicalEntry(entry: string): string {
-  if (entry === LEGACY_PLUGIN_NAME) {
-    return PLUGIN_NAME
-  }
-
-  if (entry.startsWith(`${LEGACY_PLUGIN_NAME}@`)) {
-    return `${PLUGIN_NAME}${entry.slice(LEGACY_PLUGIN_NAME.length)}`
-  }
-
-  return entry
-}
-
 export function logLegacyPluginStartupWarning(): void {
   const result = checkForLegacyPluginEntry()
   if (!result.hasLegacyEntry) {