feat(bench): automate B7 shader profiles, wire B12b trials, settle 45s

- gen_shader_profiles.py + shader-profiles/: Iris per-pack option files
  resolved from each pack's profile.* lines (Iris has no profile key)
- bench.py: flag rows shader_not_loaded when Iris falls back to vanilla
  rendering (analyze.py treats it as invalid)
- matrix: shader_options session key, trial jar globs pinned to the
  downloaded Modrinth builds, post-join settle 45 s (B0 v1 showed rep 1
  still warming at 10 s)

analysis/client-perf/harness/shader-profiles/MakeUp-UltraFast-9.5f.shadowless_medium.txt

@@ -0,0 +1,33 @@
+# Iris options reproducing profile.shadowless_medium of MakeUp-UltraFast-9.5f.zip
+# pack sha256 afbf622b983d29ffa5fe5f15197f321d3921915bd44584d85f14bc11b5e0e5e8
+# generated by gen_shader_profiles.py - do not edit; Iris rewrites the live
+# copy keeping only non-default values (bench.py journals and restores it)
+SHADOW_CASTING=false
+SHADOW_QTY_SLIDER=1
+SHADOW_DISTANCE_SLIDER=0
+REFLECTION_SLIDER=1
+DOF=false
+DOF_STRENGTH=0.09
+AO=1
+AOSTEPS=5
+AO_STRENGTH=0.70
+AA_TYPE=0
+MOTION_BLUR=false
+REFRACTION=1
+SUN_REFLECTION=1
+WAVING=1
+V_CLOUDS=1
+CLOUD_STEPS_AVG=10
+CLOUD_VOL_STYLE=0
+BLOOM_SAMPLES=3.0
+BLOOM=false
+CHROMA_ABER=0
+VOL_LIGHT=0
+CLOUD_REFLECTION=false
+WATER_ABSORPTION=0.10
+COLOR_SCHEME=1
+VANILLA_WATER=false
+WATER_COLOR_SOURCE=0
+COLORED_SHADOW=false
+MOTION_BLUR_SAMPLES=4
+MATERIAL_GLOSS=true