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>

docs/benchmarking.md

@@ -32,7 +32,7 @@ Results are in **tokens/second (t/s)**. Higher is better.
 - `-ub SIZE` — micro-batch size (512 for Vulkan, 2048 for ROCm)
 - `-r 3` — 3 repetitions (long-context tests are slow)
 
-The `-fa 1 --no-mmap -ngl 999` flags are **mandatory** on Strix Halo to avoid crashes.
+The `-fa 1 -mmp 0 -ngl 99` flags are **mandatory** on Strix Halo to avoid crashes (`-fa 1` = flash attention, `-mmp 0` = no memory mapping, `-ngl 99` = all layers on GPU).
 
 ## Available Backends
 
@@ -42,6 +42,7 @@ The `-fa 1 --no-mmap -ngl 999` flags are **mandatory** on Strix Halo to avoid cr
 | `llama-vulkan-amdvlk` | AMDVLK | Vulkan | Fastest when it works, 2GB buffer limit |
 | `llama-rocm-6.4.4` | ROCm 6.4.4 | HIP | Proven stable |
 | `llama-rocm-7.2` | ROCm 7.2 | HIP | Latest, compiler fixes applied |
+| `llama-rocm7-nightlies` | ROCm 7 nightly | HIP | Experimental/development builds |
 
 Containers are from [kyuz0/amd-strix-halo-toolboxes](https://github.com/kyuz0/amd-strix-halo-toolboxes). Set up with `make benchmark-setup`.