Fix P1S/P1P FTP upload failures

 Removed P1S and P1P from SKIP_SESSION_REUSE_MODELS
- These printers use vsFTPd which requires SSL session reuse on data channel
- Only A1/A1 Mini should skip session reuse (they have issues with SSL on data channel)
- P1S/P1P were incorrectly added in commit 9969005, causing EOFError on FTP upload

Closes #266

backend/app/services/bambu_ftp.py

@@ -78,8 +78,8 @@ class BambuFTPClient:
     FTP_PORT = 990
     DEFAULT_TIMEOUT = 30  # Default timeout in seconds (increased for A1 printers)
     # Models that need SSL session reuse disabled (A1 series has FTP issues with session reuse)
-    # P2S should use normal session reuse like X1C/P1S, not skip it
-    SKIP_SESSION_REUSE_MODELS = ("A1", "A1 Mini", "P1S", "P1P")
+    # X1C/X1E/P1S/P1P/P2S use vsFTPd which requires SSL session reuse - do NOT add them here
+    SKIP_SESSION_REUSE_MODELS = ("A1", "A1 Mini")
 
     def __init__(
         self,