fix(migration): return true when canonical config write succeeds regardless of archive status (#3133)

Previously returned archivedLegacyConfig which was false when archive
rename failed, even though the canonical file was successfully written.
Archive failure is secondary cleanup and should not be reported as
migration failure.

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src/shared/migrate-legacy-config-file.ts

@@ -58,7 +58,7 @@ export function migrateLegacyConfigFile(legacyPath: string): boolean {
       to: canonicalPath,
       archivedLegacyConfig,
     })
-    return archivedLegacyConfig
+    return true
   } catch (error) {
     log("[migrateLegacyConfigFile] Failed to migrate legacy config file", { legacyPath, error })
     return false