Revert classify.txt version floors to fix ARM64 blast solver conflict

blast>=2.17.0 does not exist on ARM64. Revert to the floors from the
last successful build (blast>=2.15.0 and other classify tool floors).

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: dpark01

docker/requirements/classify.txt

@@ -1,9 +1,9 @@
 # Metagenomic classification tools
 # Note: x86-only packages (bmtagger, kallisto, kb-python) are in classify-x86.txt
-anndata>=0.12.10
-blast>=2.17.0
-kma>=1.6.8
-kmc>=3.2.4
-kraken2>=2.17.1
+anndata>=0.10
+blast>=2.15.0
+kma>=1.4.0
+kmc>=3.2.1
+kraken2>=2.1.3
 krona>=2.8.1
-last>=1650
+last>=1541