Move Odin renderer into gui/ with per-project Makefiles

Each sub-project (gui, api, infra) now owns its own Makefile, and the
root Makefile is a lean delegator for the base commands (run, build,
test, clean, fmt). Odin source, deps, and web assets live under gui/
(gui/src, gui/lib, gui/www), with scripts kept under gui/scripts for
build tooling only.

gui/Makefile

@@ -0,0 +1,46 @@
+# gui/Makefile — the Odin + raylib renderer (the interactive 3D universe map).
+#
+# This is the Odin sub-project. It is normally invoked from the repo root via
+# `make run`, `make build`, etc. (which delegate here through the root
+# Makefile), but it can also be driven directly with `make -C gui <target>`.
+#
+# `lib/` (third-party Odin deps) lives under `gui/lib`; the `bin/` / `build/`
+# output dirs live at the repo root and are referenced through `$(ROOT)`.
+
+ODIN         ?= odin
+ROOT         := ..
+BIN          := $(ROOT)/bin
+BINARY       := $(BIN)/desi_explorer
+ODIN_FLAGS   := -collection:lib=lib/local
+WASM_DEFINE  := RAYLIB_WASM_LIB=env.o
+
+.PHONY: help run build build-debug build-web test clean fmt
+
+help: ## List available targets
+	@grep -E '^[a-zA-Z_-]+:.*?## .*$$' $(MAKEFILE_LIST) | \
+		awk 'BEGIN {FS = ":.*?## "}; {printf "  \033[36m%-18s\033[0m %s\n", $$1, $$2}'
+
+run: ## Run the native app
+	@mkdir -p lib/local
+	$(ODIN) run src $(ODIN_FLAGS)
+
+build: ## Release build -> bin/desi_explorer
+	@mkdir -p lib/local $(BIN)
+	$(ODIN) build src $(ODIN_FLAGS) -o:speed -out:$(BINARY)
+
+build-debug: ## Debug build -> bin/desi_explorer
+	@mkdir -p lib/local $(BIN)
+	$(ODIN) build src $(ODIN_FLAGS) -o:none -debug -out:$(BINARY)
+
+build-web: ## WebAssembly build -> build/web (needs emscripten)
+	@scripts/build_web.sh
+
+test: ## Run Odin unit tests
+	@mkdir -p lib/local
+	$(ODIN) test src $(ODIN_FLAGS)
+
+clean: ## Remove build artifacts
+	rm -rf $(BIN) build
+
+fmt: ## Format Odin sources with odinfmt
+	odinfmt src

gui/lib/README.md

@@ -0,0 +1,11 @@
+# Libraries
+
+Third-party libraries for the DESI Explorer renderer live here, either as git
+submodules or vendored directly and wired in via `-collection:lib=lib/local`
+(as resolved from the `gui/` directory).
+
+- `raylib` is bundled with Odin and imported as `vendor:raylib` — it does **not**
+  live in this directory.
+
+No external dependencies yet. `local/` is the default `-collection:lib` target
+and is currently empty.

gui/lib/local/.gitkeep

@@ -0,0 +1 @@
+# Intentionally empty; third-party Odin deps are wired in via -collection:lib=lib/local.

gui/odinfmt.json

@@ -0,0 +1,5 @@
+{
+  "character_width": 80,
+  "tabs": true,
+  "tabs_width": 2
+}

gui/ols.json

@@ -0,0 +1,15 @@
+{
+  "collections": [
+    { "name": "app", "path": "./src" },
+    { "name": "lib", "path": "./lib" }
+  ],
+  "enable_semantic_tokens": false,
+  "enable_document_symbols": true,
+  "enable_hover": true,
+  "enable_snippets": true,
+  "profiles": [
+    {
+      "checker_path": "src/main.odin"
+    }
+  ]
+}

gui/scripts/build_web.sh

@@ -0,0 +1,54 @@
+#!/usr/bin/env bash
+# Builds the WebAssembly ("web") build of DESI Explorer with Odin
+# (js_wasm32) + emscripten. Output: build/web/index.html (+ index.wasm,
+# odin.js) at the repo root. Run via `make -C gui build-web`.
+#
+# Requires:
+#   - `odin` on PATH with the js_wasm32 target
+#   - emcc / emscripten active in PATH
+# Optional:
+#   - ODIN_ROOT (defaults to `odin root`)
+#   - OUT_DIR   (defaults to <repo>/build/web)
+set -euo pipefail
+
+# Resolve the gui/ project root so this script works regardless of CWD.
+SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+GUI_DIR="$(cd "${SCRIPT_DIR}/.." && pwd)"
+ROOT_DIR="$(cd "${GUI_DIR}/.." && pwd)"
+
+OUT_DIR="${OUT_DIR:-${ROOT_DIR}/build/web}"
+ODIN_ROOT="${ODIN_ROOT:-$(odin root)}"
+
+mkdir -p "${GUI_DIR}/lib/local"
+mkdir -p "$OUT_DIR"
+
+# The Odin compiler emits a wasm object; raylib's C code is linked later by
+# emcc. `-define:RAYLIB_WASM_LIB=env.o` stops the compiler from trying to
+# link the raylib lib itself (emcc does that; it ends up in the final module).
+odin build "${GUI_DIR}/src" \
+  -target:js_wasm32 \
+  -build-mode:obj \
+  -define:RAYLIB_WASM_LIB=env.o \
+  -o:speed \
+  -collection:lib="${GUI_DIR}/lib/local" \
+  -out:"${OUT_DIR}/game"
+
+# Odin's JS runtime glue; the generated module imports functions from it.
+cp "${ODIN_ROOT}/core/sys/wasm/js/odin.js" "${OUT_DIR}/odin.js"
+
+# Link with emscripten against raylib's prebuilt web library. Flags mirror the
+# known-good karl-zylinski/odin-raylib-web template.
+emcc \
+  -o "${OUT_DIR}/index.html" \
+  "${OUT_DIR}/game.obj" \
+  "${ODIN_ROOT}/vendor/raylib/wasm/libraylib.web.a" \
+  --shell-file "${GUI_DIR}/www/index_template.html" \
+  -sEXPORTED_RUNTIME_METHODS="['HEAPF32']" \
+  -sUSE_GLFW=3 \
+  -sWASM_BIGINT \
+  -sWARN_ON_UNDEFINED_SYMBOLS=0 \
+  -sASSERTIONS
+
+rm -f "${OUT_DIR}/game.obj"
+
+echo "Web build created in ${OUT_DIR}"

gui/src/main.odin

@@ -0,0 +1,113 @@
+package main
+
+import "core:math"
+import "core:math/rand"
+import rl "vendor:raylib"
+
+WIDTH :: 1280
+HEIGHT :: 720
+
+// Number of procedurally generated points standing in for the DESI catalog.
+// This is replaced by real survey data once ingestion lands.
+POINT_COUNT :: 4_000
+WORLD_RADIUS :: f32(500.0)
+
+Galaxy :: struct {
+	position: rl.Vector3,
+	color:    rl.Color,
+}
+
+camera: rl.Camera3D
+universe: [dynamic]Galaxy
+
+// Deterministic generator so the placeholder sky is stable between runs.
+rng: rand.Default_Random_State
+
+main :: proc() {
+	rng = rand.create(0xDE51_0000)
+	context.random_generator = rand.default_random_generator(&rng)
+
+	rl.SetConfigFlags({.WINDOW_RESIZABLE, .VSYNC_HINT, .MSAA_4X_HINT})
+	rl.InitWindow(WIDTH, HEIGHT, "DESI Explorer")
+	defer rl.CloseWindow()
+	rl.SetTargetFPS(60)
+
+	camera = make_camera()
+	make_universe(&universe, POINT_COUNT)
+	defer delete(universe)
+
+	for !rl.WindowShouldClose() {
+		update()
+		draw()
+	}
+}
+
+make_camera :: proc() -> rl.Camera3D {
+	return {
+		position = {0, 220, 220},
+		target = {0, 0, 0},
+		up = {0, 1, 0},
+		fovy = 60,
+		projection = .PERSPECTIVE,
+	}
+}
+
+make_universe :: proc(u: ^[dynamic]Galaxy, count: int) {
+	clear(u)
+	reserve(u, count)
+	for _ in 0 ..< count {
+		pos := random_sphere_point(WORLD_RADIUS)
+		append(u, Galaxy{position = pos, color = color_for_position(pos)})
+	}
+}
+
+// Uniformly distributed random point inside the scene's bounding sphere.
+random_sphere_point :: proc(radius: f32) -> rl.Vector3 {
+	for {
+		x := rand.float32_range(-1, 1)
+		y := rand.float32_range(-1, 1)
+		z := rand.float32_range(-1, 1)
+		len_sq := x * x + y * y + z * z
+		if len_sq > 0.0001 && len_sq < 1.0 {
+			return {x * radius, y * radius, z * radius}
+		}
+	}
+}
+
+// Maps distance from the origin to a blue (near) -> red (far) gradient, a
+// stand-in for redshift until real colors are computed from survey metadata.
+color_for_position :: proc(p: rl.Vector3) -> rl.Color {
+	d := math.sqrt(p.x * p.x + p.y * p.y + p.z * p.z)
+	t := math.clamp(d / WORLD_RADIUS, 0, 1)
+	return rl.Color{u8(40 + 180 * t), 120, u8(255 - 180 * t), 255}
+}
+
+update :: proc() {
+	// Orbital camera: drag to rotate, scroll to zoom, right-drag / shift to pan.
+	rl.UpdateCamera(&camera, .ORBITAL)
+}
+
+draw :: proc() {
+	rl.BeginDrawing()
+	defer rl.EndDrawing()
+
+	rl.ClearBackground({5, 5, 15, 255})
+
+	rl.BeginMode3D(camera)
+	defer rl.EndMode3D()
+
+	rl.DrawGrid(20, 50.0)
+
+	for galaxy in universe {
+		rl.DrawPoint3D(galaxy.position, galaxy.color)
+	}
+
+	rl.DrawFPS(10, 10)
+	rl.DrawText(
+		"DESI Explorer — drag to rotate, scroll to zoom",
+		10,
+		34,
+		18,
+		rl.RAYWHITE,
+	)
+}

gui/www/index_template.html

@@ -0,0 +1,50 @@
+<!doctype html>
+<html lang="en">
+<head>
+	<meta charset="utf-8">
+	<title>DESI Explorer</title>
+	<meta name="viewport" content="width=device-width">
+	<style>
+		body {
+			margin: 0;
+			overflow: hidden;
+			background: #05050f;
+		}
+		canvas {
+			display: block;
+		}
+	</style>
+</head>
+<body>
+	<canvas id="canvas" tabindex="-1" oncontextmenu="event.preventDefault()"></canvas>
+
+	<!-- Odin's JS runtime glue; required by the generated wasm module. -->
+	<script src="odin.js"></script>
+
+	<script>
+		var odinMemoryInterface = new odin.WasmMemoryInterface();
+		odinMemoryInterface.setIntSize(4);
+		var odinImports = odin.setupDefaultImports(odinMemoryInterface);
+
+		var Module = {
+			instantiateWasm: function(imports, successCallback) {
+				var newImports = Object.assign({}, odinImports, imports);
+				return WebAssembly.instantiateStreaming(fetch("index.wasm"), newImports).then(
+					function(output) {
+						var e = output.instance.exports;
+						odinMemoryInterface.setExports(e);
+						odinMemoryInterface.setMemory(e.memory);
+						return successCallback(output.instance);
+					}
+				);
+			},
+			onRuntimeInitialized: function() {
+				var e = wasmExports;
+				if (e._start) { e._start(); }
+			},
+			canvas: document.getElementById("canvas")
+		};
+	</script>
+	{{{ SCRIPT }}}
+</body>
+</html>