feat: add rawTranscriptContent field to SessionImport model

feat: enhance server initialization with environment validation and import processing scheduler

test: add Jest setup for unit tests and mock console methods

test: implement unit tests for environment management and validation

test: create unit tests for transcript fetcher functionality

prisma/schema.prisma

@@ -155,6 +155,9 @@ model SessionImport {
   category               String?
   initialMessage         String?
 
+  // ─── Raw transcript content ─────────────────────────
+  rawTranscriptContent   String? // Fetched content from fullTranscriptUrl
+
   // ─── bookkeeping ─────────────────────────────────
   status      ImportStatus @default(QUEUED)
   errorMsg    String?