docs: client-perf analysis, bench harness and work journal

Everything the next agent needs to run the Phase 2 optimisation loop on a
machine that can launch the client:

- analysis/client-perf/: LEVERS (ranked levers + corrections), BENCH-MATRIX
  (world, scenes, config IDs, blocks B0-B14 with decision rules),
  PLAYER-TUNING, SPAWN-TUNING, research briefs, the jar scanner and its
  output, observed default configs, and proposed-configs/ (build.py
  generates tiers and bench variants and fails on unknown keys;
  apply_variant.py applies a variant and merges options.txt).
- analysis/client-perf/bench/onion-bench/: bench-world datapack (scene
  teleports, Create grid, mob pen, sound storm, 120 s teleport tour).
- analysis/audit/: the static recipe/dependency audit, including gen_fixes.py,
  which generates the shipped Paxi datapack and was never tracked.
- phase0/: per-machine measurement harness (Steam Deck, 7700K/1060,
  6700K/1080 Ti).
- .pi/journal.md: running work log; read it first.

All of it is packwizignored, so nothing here ships to players.

analysis/client-perf/data/observed-default-configs/sound_physics_remastered/reflectivity.properties

@@ -0,0 +1,213 @@
+# Values for blocks can be defined as follows:
+# 
+# By sound type:
+# WOOD=1.0
+# 
+# By block tag:
+# \#minecraft\:logs=1.0
+# 
+# By block ID:
+# minecraft\:oak_log=1.0
+
+# Amethyst (Sound Type)
+AMETHYST=1.5
+# Amethyst Cluster (Sound Type)
+AMETHYST_CLUSTER=0.5
+# Ancient Debris (Sound Type)
+ANCIENT_DEBRIS=0.5
+# Anvil (Sound Type)
+ANVIL=0.5
+# Azalea (Sound Type)
+AZALEA=0.5
+# Azalea Leaves (Sound Type)
+AZALEA_LEAVES=0.5
+# Bamboo (Sound Type)
+BAMBOO=0.5
+# Bamboo Sapling (Sound Type)
+BAMBOO_SAPLING=0.5
+# Bamboo Wood (Sound Type)
+BAMBOO_WOOD=0.5
+# Bamboo Wood Hanging Sign (Sound Type)
+BAMBOO_WOOD_HANGING_SIGN=0.5
+# Basalt (Sound Type)
+BASALT=1.5
+# Big Dripleaf (Sound Type)
+BIG_DRIPLEAF=0.5
+# Bone Block (Sound Type)
+BONE_BLOCK=1.5
+# Calcite (Sound Type)
+CALCITE=1.5
+# Candle (Sound Type)
+CANDLE=0.5
+# Cave Vines (Sound Type)
+CAVE_VINES=0.5
+# Chain (Sound Type)
+CHAIN=0.5
+# Cherry Leaves (Sound Type)
+CHERRY_LEAVES=0.5
+# Cherry Sapling (Sound Type)
+CHERRY_SAPLING=0.5
+# Cherry Wood (Sound Type)
+CHERRY_WOOD=0.5
+# Cherry Wood Hanging Sign (Sound Type)
+CHERRY_WOOD_HANGING_SIGN=0.5
+# Chiseled Bookshelf (Sound Type)
+CHISELED_BOOKSHELF=0.5
+# Copper (Sound Type)
+COPPER=1.25
+# Coral Block (Sound Type)
+CORAL_BLOCK=0.2
+# Crop (Sound Type)
+CROP=0.5
+# Decorated Pot (Sound Type)
+DECORATED_POT=0.5
+# Decorated Pot Cracked (Sound Type)
+DECORATED_POT_CRACKED=0.5
+# Deepslate (Sound Type)
+DEEPSLATE=1.5
+# Deepslate Bricks (Sound Type)
+DEEPSLATE_BRICKS=1.5
+# Deepslate Tiles (Sound Type)
+DEEPSLATE_TILES=1.5
+# Dripstone Block (Sound Type)
+DRIPSTONE_BLOCK=0.5
+# Flowering Azalea (Sound Type)
+FLOWERING_AZALEA=0.5
+# Froglight (Sound Type)
+FROGLIGHT=0.5
+# Frogspawn (Sound Type)
+FROGSPAWN=0.5
+# Fungus (Sound Type)
+FUNGUS=0.5
+# Gilded Blackstone (Sound Type)
+GILDED_BLACKSTONE=0.5
+# Glass (Sound Type)
+GLASS=0.75
+# Glow Lichen (Sound Type)
+GLOW_LICHEN=0.5
+# Grass (Sound Type)
+GRASS=0.3
+# Gravel (Sound Type)
+GRAVEL=0.3
+# Hanging Roots (Sound Type)
+HANGING_ROOTS=0.5
+# Hanging Sign (Sound Type)
+HANGING_SIGN=0.5
+# Hard Crop (Sound Type)
+HARD_CROP=0.5
+# Honey Block (Sound Type)
+HONEY_BLOCK=0.1
+# Ladder (Sound Type)
+LADDER=0.5
+# Lantern (Sound Type)
+LANTERN=0.5
+# Large Amethyst Bud (Sound Type)
+LARGE_AMETHYST_BUD=0.5
+# Lily Pad (Sound Type)
+LILY_PAD=0.5
+# Lodestone (Sound Type)
+LODESTONE=0.5
+# Mangrove Roots (Sound Type)
+MANGROVE_ROOTS=0.5
+# Medium Amethyst Bud (Sound Type)
+MEDIUM_AMETHYST_BUD=0.5
+# Metal (Sound Type)
+METAL=1.25
+# Moss (Sound Type)
+MOSS=0.1
+# Moss Carpet (Sound Type)
+MOSS_CARPET=0.5
+# Mud (Sound Type)
+MUD=0.5
+# Muddy Mangrove Roots (Sound Type)
+MUDDY_MANGROVE_ROOTS=0.5
+# Mud Bricks (Sound Type)
+MUD_BRICKS=0.5
+# Netherite Block (Sound Type)
+NETHERITE_BLOCK=1.5
+# Netherrack (Sound Type)
+NETHERRACK=1.1
+# Nether Bricks (Sound Type)
+NETHER_BRICKS=1.5
+# Nether Gold Ore (Sound Type)
+NETHER_GOLD_ORE=1.1
+# Nether Ore (Sound Type)
+NETHER_ORE=1.1
+# Nether Sprouts (Sound Type)
+NETHER_SPROUTS=0.5
+# Nether Wart (Sound Type)
+NETHER_WART=0.5
+# Nether Wood (Sound Type)
+NETHER_WOOD=0.5
+# Nether Wood Hanging Sign (Sound Type)
+NETHER_WOOD_HANGING_SIGN=0.5
+# Nylium (Sound Type)
+NYLIUM=0.5
+# Packed Mud (Sound Type)
+PACKED_MUD=0.5
+# Pointed Dripstone (Sound Type)
+POINTED_DRIPSTONE=0.5
+# Polished Deepslate (Sound Type)
+POLISHED_DEEPSLATE=1.5
+# Powder Snow (Sound Type)
+POWDER_SNOW=0.5
+# Rooted Dirt (Sound Type)
+ROOTED_DIRT=0.5
+# Roots (Sound Type)
+ROOTS=0.5
+# Sand (Sound Type)
+SAND=0.2
+# Scaffolding (Sound Type)
+SCAFFOLDING=0.5
+# Sculk (Sound Type)
+SCULK=0.5
+# Sculk Catalyst (Sound Type)
+SCULK_CATALYST=0.5
+# Sculk Sensor (Sound Type)
+SCULK_SENSOR=0.5
+# Sculk Shrieker (Sound Type)
+SCULK_SHRIEKER=0.5
+# Sculk Vein (Sound Type)
+SCULK_VEIN=0.5
+# Shroomlight (Sound Type)
+SHROOMLIGHT=0.5
+# Slime Block (Sound Type)
+SLIME_BLOCK=0.5
+# Small Amethyst Bud (Sound Type)
+SMALL_AMETHYST_BUD=0.5
+# Small Dripleaf (Sound Type)
+SMALL_DRIPLEAF=0.5
+# Snow (Sound Type)
+SNOW=0.15
+# Soul Sand (Sound Type)
+SOUL_SAND=0.2
+# Soul Soil (Sound Type)
+SOUL_SOIL=0.2
+# Spore Blossom (Sound Type)
+SPORE_BLOSSOM=0.5
+# Stem (Sound Type)
+STEM=0.4
+# Stone (Sound Type)
+STONE=1.5
+# Suspicious Gravel (Sound Type)
+SUSPICIOUS_GRAVEL=0.5
+# Suspicious Sand (Sound Type)
+SUSPICIOUS_SAND=0.5
+# Sweet Berry Bush (Sound Type)
+SWEET_BERRY_BUSH=0.5
+# Tuff (Sound Type)
+TUFF=1.5
+# Twisting Vines (Sound Type)
+TWISTING_VINES=0.5
+# Vine (Sound Type)
+VINE=0.5
+# Wart Block (Sound Type)
+WART_BLOCK=0.5
+# Weeping Vines (Sound Type)
+WEEPING_VINES=0.5
+# Wet Grass (Sound Type)
+WET_GRASS=0.5
+# Wood (Sound Type)
+WOOD=0.4
+# Wool (Sound Type)
+WOOL=0.1