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/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"
+    }
+  ]
+}