fix(docs): address review findings — accuracy, consistency, completeness

- architecture.md: fix kernel param math to match actual computed values,
  use cardN placeholder in sysfs paths, clarify system_ram_kb is OS-visible
- benchmarking.md: normalize flags to -ngl 99 / -mmp 0 (matching code),
  add llama-rocm7-nightlies backend
- CLAUDE.md: clarify HSA_OVERRIDE_GFX_VERSION is set in containers not
  scripts, fix lib sourcing description, specify which scripts need root
- detect.sh: document detect_cpu_cores returns threads not cores
- troubleshooting.md: add link to references.md
- README.md: remove unsupported Fedora 42 claim, describe configs/ content

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

lib/detect.sh

@@ -24,8 +24,8 @@ GPU_SYSFS="$(find_gpu_card)"
 
 # --- CPU ---
 detect_cpu_model()   { grep -m1 'model name' /proc/cpuinfo | cut -d: -f2 | xargs; }
-detect_cpu_cores()   { grep -c '^processor' /proc/cpuinfo; }
-detect_cpu_physical() { grep 'cpu cores' /proc/cpuinfo | head -1 | cut -d: -f2 | xargs; }
+detect_cpu_cores()   { grep -c '^processor' /proc/cpuinfo; }  # logical processors (threads)
+detect_cpu_physical() { grep 'cpu cores' /proc/cpuinfo | head -1 | cut -d: -f2 | xargs; }  # physical cores
 
 # --- GPU ---
 detect_gpu_name() {