feat: add NameLen field to StatFs response and update related tests

[egalvis27]

Fix: File name is too long error when renaming files or folders

Problem

Nautilus (and other file managers) were showing "File name is too long" for any
rename attempt — even a single character — inside the Internxt virtual drive.

Root Cause

The StatFs FUSE operation never populated the NameLen / f_namelen field in the
filesystem statistics. This caused the mount to report a maximum filename length of
0 bytes. File managers call statvfs() before validating a rename; with
f_namelen = 0 every name is considered too long.

Fix

Return the standard Linux NAME_MAX value (255) in the nameLen field across
the full stack:

• statfs.service.ts — added nameLen: NAME_MAX (255) to StatFsResult and
  to the value returned by statfs().
• responses.go — added NameLen uint32 field to StatFsCallbackData so the
  Go daemon can deserialize the value from Electron.
• operations.go — set NameLen: response.NameLen in the fuse.StatfsOut
  returned to the kernel.

Tests updated

• statfs.service.test.ts — expected result now includes nameLen: 255.
• statfs.controller.test.ts — test fixture updated with nameLen: 255.
• operations_test.go — mock response includes nameLen and asserts
  stat.Namelen == 255.

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
100.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud