Docs: session log Part R + roadmap tick — Phase 1.5b bundle 4 shipped, 1.5b COMPLETE

Bundle 4 (critters + weather beats) shipped; all four World-Alive-II bundles
done. Next = the operator's Phase 1.5 gate lap.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Docs/Vault/07_Sessions/2026/2026-07-09_B4d_Tail_Collision_Grounding.md

@@ -395,14 +395,37 @@ the barrel/cover chassis + bundle-2's scorch pool.
   Blight ground, and whether a distinct geyser mesh (interim = the ResourceNode mesh) is wanted. Knobs:
   `Tuning.Geyser*` (period/telegraph/radius/damage) + `GeyserFieldSpawner.Count`.
 
+## Part R — Phase 1.5b bundle 4 (CRITTERS + WEATHER BEATS) shipped — PHASE 1.5b COMPLETE
+
+The last locked 1.5b bundle, all **client-only, procedural, zero netcode** — one new sibling of
+`AmbientMotionSystem`: **`AmbientLifeSystem`** (+ `AmbientLifeConfig` static knobs), scene-gated "Game",
+camera-following, biome-keyed off the same camera-X + replicated `RunInfo.CurrentBiome` switch. Three beats:
+- **Fleeing critters** — a pooled set of ground BUGS (+ a `BirdFraction` of airborne BIRDS) that idle-wander
+  near the camera and DART away when the local player closes inside `CritterFleeRadius` (the "scatter" beat),
+  biome-tinted (meadow pale / arid tan / cavern blue / blight purple), recycled at the ring edge. Reuses
+  `FeedbackFx.BuildDisc` specks + `MakeParticleMaterial`.
+- **Cloud-shadow drifts** — soft dark feathered discs (`FeedbackFx.BuildScorchMesh`) drifting slowly across the
+  ground on a light prevailing wind, recycled off the downwind edge.
+- **Blight lightning** — Blight rooms ONLY: a periodic (`LightningMin/MaxInterval`) double-blink DIRECTIONAL
+  flash light (created lazily; never touches `RenderSettings`, so no fight with `WorldAtmosphereSystem`) + a
+  delayed procedural thunder rumble.
+- **Verified:** console clean · 474/474 EditMode (no regression; pure presentation, no new tests) · **live at
+  base** — `~AmbientLife` root with 7 bugs + 3 birds + 3 cloud shadows, sample bug on the ground with the exact
+  meadow tint, and the **flee beat confirmed** (nearest critter clustered at 4.62u = just outside the 4u flee
+  radius — they scatter out of the zone, not a static pool); NO lightning light at base (Blight-gated, correct);
+  no exceptions. Blight lightning's visual → the operator's Blight-room gate lap (biome-gated like the geyser).
+  Knobs: `AmbientLifeConfig` (counts/radii/speeds/colors/intervals).
+
 ## Next-session intent
 
-**Phase 1.5b bundles 1 (ground) + 2 (decals) + 3 (Blight geyser) are SHIPPED.** Last locked bundle: **4)
-critters + weather beats** (fleeing bugs/birds · cloud-shadow drifts · Blight lightning flicker — client-only,
-likely no design review). Then the operator's 1.5 gate lap ("no longer static"; ground + decals + geyser judged
-explicitly) → Phase 1.7 boon overhaul (design-review-FIRST) → Phase 2 hub-ification. Taste queue: **geyser feel
-lap (telegraph/erupt tuning · distinct geyser mesh?)** · decals feel lap · arid brightness · craters call · B5
-split-panels smoke · barrel explosion VFX polish · flower density.
+**PHASE 1.5b (World Alive II) is COMPLETE — all four bundles shipped: ground · decals · Blight geyser ·
+critters+weather.** NEXT = the operator's **Phase 1.5 gate lap** — a "no longer static" playtest judging the
+whole World-Alive pass explicitly (ground + decals + geyser + critters/weather), with the biome-gated beats
+(geyser erupt, Blight lightning) seen in a real Blight room. If it passes → **Phase 1.7 boon overhaul
+(design-review-FIRST — ~12 mechanic-changers)** → Phase 2 hub-ification. Taste/tuning queue for the lap:
+geyser telegraph/erupt + distinct geyser mesh? · decals scorch/crack tuning · critter density/flee feel ·
+cloud-shadow opacity · Blight lightning cadence · arid brightness · craters call · B5 split-panels smoke ·
+barrel VFX · flower density. Order stays: 1.5 gate → 1.7 → 2 → 3 → 4/5 parallel.
 
 Related: [[Iteration_2026-07_CoopHades]] · [[2026-07-07_Workflow_Consolidation]] ·
 [[2026-07-07_Expedition_Enemy_Stuck_Harvest_Feedback]]