Windows review findings: reserved device names (con, nul, COM1..) and
trailing dots in server names break or desync directory creation, so
sanitize_server now escapes reserved stems, strips trailing dots, and
caps length at 64 chars. Spill writes go through a temp file + rename
so a visible file is always complete (closes a cross-process partial
read race), and eviction protection compares content-hashed file names
instead of full paths. Also drops a duplicated cfg attribute.
Dark-Alex-17
b38562a961