Move docs/ package mirror into document-navigator plugin

Relocate the ~6k-file docs tree from the repo root into
plugins/document-navigator/docs/ so the plugin is self-contained and
portable. docs/superpowers/ (specs and plans) stays at the repo root.

Moved via cp+rm rather than git mv because directory rename() fails with
EPERM on this WSL /mnt DrvFs mount; git rename-detection pairs the
identical-content files at commit time.

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

plugins/document-navigator/docs/geospatial/geo/universe/src/client/client.md

@@ -0,0 +1,138 @@
+# UniverseClient
+
+<!-- begin:auto-docs -->
+_(no submodules)_
+<!-- end:auto-docs -->
+## Purpose
+
+`UniverseClient` is the single composition point that aggregates solar, star, tidal, and weather provider implementations into one cohesive `UniverseScene` snapshot for a given observer at a given instant. It owns no domain knowledge of its own — every datum on the returned scene is delegated to a provider the consumer registered. This indirection lets the same client power a real-time astronomy app, a deterministic game world, a server-rendered ephemeris page, or a unit test, simply by swapping providers.
+
+The client is intentionally minimal: no caching, no retry, no fan-out; it propagates the caller's `AbortSignal` to every registered provider and assembles their results into one `UniverseScene` value. Tides are skipped when the observer is in space (no surface to compute against). Unregistered domains contribute empty arrays (`bodies`, `stars`) or are omitted entirely (`tides`, `weather`).
+
+## Features
+
+- Fluent registration: `registerSolar` / `registerStars` / `registerTides` / `registerWeather` chain on `this`.
+- One-shot scene assembly via `getScene(observer, time, signal?)`.
+- AbortSignal forwarded to every provider call.
+- Tides automatically skipped for `kind: "space"` observers.
+- Optional fields (`tides`, `weather`) only present when their provider is registered and produces a value.
+- Provider-agnostic — interfaces only, zero base classes.
+
+## Usage: Basic Example
+
+```ts
+import { UniverseClient } from "@suaveplan/universe";
+
+const client = new UniverseClient();
+const scene = await client.getScene(
+    { kind: "space", heliocentricVec: { x: 0, y: 0, z: 0 }, frame: "icrs" },
+    new Date()
+);
+// scene.bodies === [], scene.stars === [], scene.tides/weather undefined
+```
+
+## Usage: Advanced Example
+
+```ts
+import { UniverseClient, type UniverseScene } from "@suaveplan/universe";
+import type {
+    SolarProvider,
+    StarProvider,
+    WeatherProvider,
+} from "@suaveplan/universe";
+
+const solar: SolarProvider = {
+    async getBodies() {
+        return [];
+    },
+    async getBody(name) {
+        return {
+            name,
+            type: "star",
+            altitude: 45,
+            azimuth: 180,
+            apparentMagnitude: -26.7,
+            angularDiameterArcmin: 32,
+            distanceAu: 1,
+            heliocentricPosition: { x: 0, y: 0, z: 0 },
+        };
+    },
+    async getSunrise() {
+        return new Date("2026-01-01T06:00:00Z");
+    },
+    async getSunset() {
+        return new Date("2026-01-01T18:00:00Z");
+    },
+};
+
+const stars: StarProvider = {
+    async getVisibleStars() {
+        return [];
+    },
+    async queryCone() {
+        return [];
+    },
+    async getStar() {
+        return null;
+    },
+};
+
+const weather: WeatherProvider = {
+    async getCurrent() {
+        return { temperature: 18, pressure: 1015, humidity: 60 };
+    },
+};
+
+const controller = new AbortController();
+const client = new UniverseClient()
+    .registerSolar(solar)
+    .registerStars(stars)
+    .registerWeather(weather);
+
+const scene: UniverseScene = await client.getScene(
+    {
+        kind: "surface",
+        planet: {
+            name: "Earth",
+            mass: 1,
+            radius: 1,
+            polarRadius: 1,
+            surfaceGravity: 1,
+            rotationPeriod: 1,
+            axialTilt: 23.4,
+            atmosphere: null,
+            satellites: [],
+        },
+        coord: { latitude: 51.5, longitude: -0.12 },
+    },
+    new Date(),
+    controller.signal
+);
+```
+
+## API Reference
+
+### `class UniverseClient`
+
+| Method | Returns | Description |
+|---|---|---|
+| `registerSolar(provider)` | `this` | Register a `SolarProvider`. |
+| `registerStars(provider)` | `this` | Register a `StarProvider`. |
+| `registerTides(provider)` | `this` | Register a `TidalProvider`. |
+| `registerWeather(provider)` | `this` | Register a `WeatherProvider`. |
+| `getScene(observer, time, signal?)` | `Promise<UniverseScene>` | Assemble the scene. Forwards `signal` to every provider. |
+
+### `interface UniverseScene`
+
+| Property | Type | Notes |
+|---|---|---|
+| `bodies` | `CelestialBody[]` | Empty when no solar provider. |
+| `stars` | `ObservedStar[]` | Empty when no star provider. |
+| `tides?` | `TideExtreme[]` | Omitted for space observers and when no tidal provider. |
+| `weather?` | `WeatherState` | Omitted when no weather provider. |
+
+The client throws (propagates) any error a provider throws, including `AbortError` from a fired signal.
+
+## Implementation Notes
+
+`UniverseClient` is a coordinator, not a cache. Each `getScene` call invokes every registered provider unconditionally (subject to the space-tide skip). Consumers that need memoisation, retry, or rate limiting should compose those policies into the providers themselves rather than wrapping the client. Re-exporting the four provider interfaces and `WeatherState` from this module (in addition to `@suaveplan/universe/providers/providers`) is intentional so consumers can `import { type SolarProvider } from "@suaveplan/universe"` without reaching into a sub-path.