Guard against panics from unchecked type assertions

Replace two unchecked type assertions that could crash the server:

- server.go: the file-transfer logger built remoteAddr via a bare
  ctx.Value(contextKeyReq).(requestCtx) assertion, which panics if the
  context value is absent or the wrong type. Use the comma-ok form and
  degrade to an empty string.

- access.go: the legacy (< v0.17.0) AccessBitmap YAML array path used
  byte(v.(int)) with no element-type or bounds check, panicking on a
  non-int element or an array longer than the [8]byte bitmap. Iterate the
  slice from the type switch, bounds-check the index, and comma-ok each
  element, returning a wrapped error so a malformed user file fails to
  load loudly instead of crashing the server.

Add regression tests for the non-int and oversized legacy array cases.

0 files changed, 0 insertions, 0 deletions