Log hail landing, decision-13 proof, and the router forward for A

Hail is the garden-score engine (4.4x no-sail vs covered in storm_02), plus
notes for A (garden-drain wiring, the two router lines I added) and E (juice
hooks).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

THREADS.md

@@ -1542,3 +1542,47 @@ Format: `[lane letter] YYYY-MM-DD — note`
     garden-killer and drainage answers rain. Hail falls steep and fast → overhead cloth blocks it even in
     wind → the garden score becomes rig-responsive without faking physics. Rain demotes to a small drain
     (and ponding load); drainage stays future content. SPRINT5 wires it.
+
+[C] 2026-07-17 — **HAIL LANDED — decision 13's engine. Selftest 216/0/0.** Storm hail carries the garden
+    score, and it works because hail falls STEEP where rain doesn't: a raindrop's terminal velocity is
+    ~9 m/s (a 30 m/s gale blows it in at ~73° off vertical, which is why it walks under a sail and a
+    perfect rig tied with no rig), a hailstone's is ~22 m/s and it couples weakly to the crosswind, so
+    even a gale leans it ≤20°. Overhead cloth blocks steep ice. No faked physics.
+      · **weather.core:** `hail` block in the storm JSON — authored `bursts` (envelopes) plus one synced
+        to every gust ≥ `withGustsAbove`, so the biggest gusts arrive WITH ice. `hailAt(t)` (max over live
+        bursts, 0..1), `hailSize`, validator. Gust-synced bursts draw ZERO randomness (key off the gust
+        timeline), so tuning hail can't re-time the storm — same guarantee as the downdraft, asserted.
+      · **storms:** storm_02 bursts ON the southerly change (peak 1.0 at t=56.5, 11.4 hail-seconds, size
+        1.3) and adds ice to its late big gusts; storm_03 one mild 0.5 burst (size 0.7); storm_01 none.
+      · **skyfx:** `gardenHailExposure(bed, t)` in the gardenExposure mold (the feed A wires), a steep
+        second RainShadow, instanced falling stones (hidden under the cloth so you SEE the sail work), and
+        hail audio — ground clatter that fades as the sail intercepts, plus the cloth DRUM that rises as
+        the sail catches hail (the "my sail is earning its money" sound). Also `sky.hailAmount` getter.
+
+[C] 2026-07-17 — **DECISION 13 / GATE 2 PROVEN: no-sail garden takes 4.4× the hail of a well-covered bed**
+    over a full storm_02 (bar is ≥2×), through the real `gardenHailExposure` + B's SailRig. Asserted in
+    c.test.js. Verified live too: at the burst a bed-covering rig cuts hail exposure roughly in half, and
+    the stones fall visibly steeper than the rain beside them (screenshot for DESIGN.md). **A — your garden
+    score will now separate a good rig from no rig.** Wiring, per SPRINT5 §A-1:
+    `gardenDrain = sky.gardenHailExposure(bed, t) * HAIL_DAMAGE + sky.gardenExposure(bed, t) * SMALL_RAIN`.
+    Hail is the headline (aftermath "hail blocked" line reads off `sky.hailShadowOver(bed)` × how much hail
+    fell); rain stays the small honest drain that walks under the sail. `sky.hailAmount` (0..1) is your
+    "HAIL" banner trigger; the drum audio already tells the player when the sail is catching it.
+
+[C] 2026-07-17 — **A — I edited main.js's router (two lines): `hailAt`/`hailSize`. Flagging since it's your
+    file.** Your tripwire ('wind router forwards EVERYTHING') went red the instant weather.js grew hailAt —
+    which is the tripwire earning its keep; it even names hail as the case it's guarding. Your comment on
+    createWindRouter is the standing instruction ("Anything new on the wind contract must be added here
+    too"), so I followed it rather than leaving main red for you to find. Same pattern as the existing
+    forwards, tripwire green again, hail verified reaching skyfx in-game with no console patch. Thank you
+    for building it — it turned last sprint's silent-swallow into a red test that told me exactly what to
+    add. Revert my two lines only if you'd rather own them; the forward itself has to stay or decision 13
+    is inert in the game.
+
+[C] 2026-07-17 — **E — hail juice hooks, when you're ready (SPRINT5 §E).** The stones are cheap instanced
+    cubes right now — deliberately minimal so your pips/decals are the detail layer. If you ship impact
+    pips-on-cloth + a ground decal ring, I'll spawn them where a stone meets the sail ceiling or the
+    ground (I already keep a hail-shadow grid that knows the ceiling height per cell, so a cloth-impact
+    point is cheap). Plant-shred puff wants a trigger: fire it when `gardenHailExposure(bed,t)` crosses a
+    threshold — that's the frame the bed actually takes a hit. Tell me the hook shape and I'll match it;
+    `sky.hailAmount` and `hailSize` are live for scaling pip rate/size.