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/proposed-configs/templates/config/lambdynlights.toml

@@ -0,0 +1,16 @@
+mode = "fancy"
+chunk_rebuild_scheduler = "culling"
+
+[adaptive_ticking]
+slow = 5
+slower = 8
+background_sleep = true
+
+[light_sources]
+entities = true
+self = true
+water_sensitive_check = true
+beam = true
+guardian_laser = true
+sonic_boom = true
+glowing_effect = true

analysis/client-perf/proposed-configs/templates/config/modernfix-mixins.properties

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+mixin.perf.dynamic_resources=false

analysis/client-perf/proposed-configs/templates/config/sound_physics_remastered/sound_rates.properties

@@ -0,0 +1 @@
+# Partial file: SPR merges these over its generated per-sound defaults (-1 = unlimited).

analysis/client-perf/proposed-configs/templates/config/ssrd-common.toml

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+#The render distance for physics objects (SubLevels) in chunks.
+# Default: 128
+# Range: 1 ~ 1000000
+physicsRenderDistance = 128
+#The minimum render distance for physics objects (SubLevels) in chunks.
+# Default: 16
+# Range: 1 ~ 1000000
+minPhysicsRenderDistance = 16
+#The maximum render distance for physics objects (SubLevels) in chunks.
+# Default: 4096
+# Range: 1 ~ 1000000
+maxPhysicsRenderDistance = 4096

analysis/client-perf/proposed-configs/templates/options.txt

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+version:3955
+renderDistance:12
+simulationDistance:12
+biomeBlendRadius:2
+mipmapLevels:4
+entityDistanceScaling:1.0
+particles:0
+entityShadows:true
+graphicsMode:1
+maxFps:120
+enableVsync:true