fix(final-docs): exclude dropped mentors from doc access; relative in-app reminder link

Review follow-ups: mentor.getProjectFinalDocuments now filters droppedAt:null
(a dropped mentor no longer sees a team's final docs); reminder linkUrl is
relative so the in-app notification does client-side nav (email still absolutized).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

src/server/services/final-documents.ts

@@ -88,10 +88,6 @@ export async function getFinalDocumentStatusForProject(
   }
 }
 
-function baseUrl(): string {
-  return (process.env.NEXTAUTH_URL ?? 'http://localhost:3000').replace(/\/$/, '')
-}
-
 /** Build the reminder notification payload for one finalist team lead. */
 async function remindTeam(
   prisma: PrismaClient,
@@ -104,7 +100,7 @@ async function remindTeam(
     message: args.missing.length
       ? `Still needed for "${args.projectTitle}": ${args.missing.join(', ')}.`
       : `Please upload the final documents for "${args.projectTitle}".`,
-    linkUrl: `${baseUrl()}/applicant/documents`,
+    linkUrl: `/applicant/documents`, // relative → client-side nav in-app; email renderer absolutizes
     metadata: {
       projectId: args.projectId,
       projectTitle: args.projectTitle,