Interactive jelly dam diorama with reservoir, spillway, fish ladder, and power station

[Note: the creator shared a partial prompt. Wording below is theirs.] GOAL: Build "Dam Jelly", a new piece in my "Material Studies" series: a single-file, self-contained interactive WebGPU diorama (one HTML file, all JS/CSS/WGSL inline, no network requests, no libraries). MOTION: A mountain valley with a concrete gravity dam is cut out as a wobbly block of jelly sitting on a pale studio table, seen from above at three-quarters. SCENE (block-local coords, origin at base centre, y up, block ~5.2 × 5.2 units): - A river valley running back to front: steep rocky slopes with crags, scree and boulders, conifer and broadleaf woods, grassy shoulders. Where the block is cut, the side faces show layered grey bedrock in tilted beds with joints, a weathered brown band and dark topsoil at the top, and gravel and silt under the water. At the very bottom are thin coloured "jelly" strata in the current flavour. - A long reservoir behind the dam, with a bare drawdown ring of rock round its shore, a floating log boom of orange and yellow floats in front of the spillway, and a small patrol boat lapping the lake. - A concrete gravity dam across the valley, its ends let into rock abutments: a battered downstream face with lift lines, a crest road with railings and lamps, an intake tower with trash racks and three penstocks down the face. - A central stepped spillway with three bays between piers. Each bay has a radial (Tainter) gate: a curved skin plate on arms that swing about trunnions on the piers, with hoist houses on top. Below is an ogee crest, a stepped chute, training walls and a plunge pool scoured into the riverbed. - A powerhouse at the right toe: a concrete base in the river, a hall of siding and tall windows, tailrace mouths. Above it, a switchyard on a terrace with transformers and gantries, and lattice pylons climbing the right slope with sagging lines. - A fish ladder up the left bank: 14 stepped concrete pools with weirs between them from the river up to the lake, an exit gate and a counting hut at the top. - A visitor centre on the left abutment, roads with hairpins, a suspension footbridge over the river downstream, rocks, weed and gravel bars in the river. SIMULATION: - Shallow-water heightfield (about 168×168), split into two bodies by the dam (reservoir and river), each with its own still level, separated by flood-fill classification. Sources, sinks and current jets make visible flow: inflow at the back of the lake, a draw toward open gates and the intake, boiling outflow in the plunge pool and tailrace, and drainage at the front edge. Foam advects on the currents. - Reservoir level ODE: dL/dt = (Qin − Qspill − Qturbines − Qover) / AREA, where Qspill ∝ gateOpening · (L − sill)^1.5 and Qover ∝ (L − crest)^1.5. The river level rises with total outflow. - Head-based power: 3 units × 120 MW, scaled by head. - An automatic dam keeper opens the gates (siren first) when the lake nears the crest or a flood is coming, and shuts them again once the water is back down. - The jelly block itself wobbles, can be tipped by dragging