Fix Axolotl ReLoRA optimizer reset scope (#3646)

* Fix Axolotl ReLoRA optimizer reset scope
* fix: make relora reset method honor relora_prune_ratio

When relora_prune_method='reset' and relora_prune_ratio is explicitly
set, the ratio was silently ignored and replaced with the hardcoded
_FULL_RESET_RATIO (0.999). Fix by moving the default-ratio logic to
ReLoRACallback.on_step_begin: None maps to _FULL_RESET_RATIO for reset
and 0.9 for other methods. reset_optimizer now uses the same random
pruning path for both 'random' and 'reset'.

Also consolidate three-layer default mismatch: schema default for
relora_prune_method is now 'magnitude' (single canonical source);
dataclass defaults for both fields changed to None to eliminate the
conflicting fallback layer.

Tests updated: removed the test case that verified the old broken
behavior (reset ignoring ratio), added two cases proving reset honors
the passed ratio. E2E reset fixture now uses ratio=0.5 to make it
unambiguous that the ratio is honored.

* Fix ReLoRA uint8 pruning regression

---------

Signed-off-by: Wing Lian <wing@axolotl.ai>
Co-authored-by: Axolotl Swarm <no-reply@axolotl.ai>

.github/workflows/tests.yml

@@ -72,7 +72,7 @@ jobs:
         exclude:
           - python_version: "3.14"
             pytorch_version: "2.9.1"
-    timeout-minutes: 20
+    timeout-minutes: 25
 
     steps:
       - name: cleanup node