feat(import): O(1) attention options in Advanced (cortiq >= 0.2.0)

- New Advanced controls on the import page: O(1) attention spec (off / all /
  deep N / explicit layer list) plus the --o1-m / --o1-window / --o1-sink knobs
  with validated defaults (32 / 128 / 4) and explanatory hints.
- Backend passes --o1* to the native `cortiq convert`; fails fast with clear
  messages when combined with Python-only options, used on GGUF imports, or
  when the installed cortiq predates 0.2.0 (the hint needs the new runtime).
- The hint is recorded in the .cmf header (weights byte-identical); the runtime
  applies it at load. Verified end-to-end: converted a model with --o1 all and
  the runtime logged "o1 nystrom attention: 2/2 layer(s)".

src/cmf_runtime.rs

@@ -238,7 +238,7 @@ fn parse_ver(s: &str) -> (u32, u32, u32) {
     )
 }
 
-fn version_lt(a: &str, b: &str) -> bool {
+pub(crate) fn version_lt(a: &str, b: &str) -> bool {
     parse_ver(a) < parse_ver(b)
 }