feat(stdlib): Tiled P0.5 — TMX/TSX reader over the XML reader (#68)

Tiled.read / Tiled.read_tsx (runtime/native/tiled.ludic): map the native
XML formats (TMX/TSX/TX) onto the SAME intermediate the JSON path produces
— a Value tree in Tiled's JSON schema — so one format-independent core
(P1) consumes either reader.

- tmx_to_value walks a <map> into {orientation, width/height, tilewidth/
  height, tilesets[], layers[]}; every tile layer's <data> is decoded to a
  dense GID int list (CSV split, or base64 -> zlib/gzip inflate ->
  little-endian u32s), so a CSV .tmx and a base64 .tmj of the same map read
  structurally identically.
- External tilesets keep the {firstgid, source} reference (as TMJ does);
  embedded tilesets and standalone .tsx (tsx_to_value) inline full geometry
  + per-tile metadata (animation frames, collision objectgroup, class,
  properties) for later phases.
- Object layers, shapes (rect/ellipse/point/polygon/polyline/text),
  image/group layers and custom properties are parsed into the tree now so
  P2/P4/P5 just read it.
- tmj_normalize decodes base64 `data` strings in a parsed .tmj so the JSON
  path matches the XML path.

Proven by library/tiled_p05.ludic (30 assertions) incl. the in-repo Kenney
sampleMap.tmx + external sampleSheet.tsx and TMX-vs-TMJ structural
identity. Docs + inventory added; x test: 91 passed.

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

docs/language/tiled/_section.md

@@ -0,0 +1,7 @@
+---
+id: tiled
+title: Tiled
+order: 42
+---
+
+Load and draw <a href="https://www.mapeditor.org/">Tiled</a> maps. Both native format families — TMX/TSX/TX (XML) and TMJ/TSJ/TJ (JSON) — read onto one intermediate, a <a href="value"><code>Value</code></a> tree in Tiled's JSON schema, with layer data decoded to a dense GID list; so a CSV <code>.tmx</code> and a base64+zlib <code>.tmj</code> of the same map read identically. <a href="tiled-read"><code>Tiled.read</code></a> returns that intermediate tree for a map file and <a href="tiled-read_tsx"><code>Tiled.read_tsx</code></a> for a tileset file. Spliced on demand when a program mentions <code>Tiled.*</code>, alongside the <a href="xml"><code>Xml</code></a>, <a href="base64"><code>Base64</code></a> and <a href="value"><code>Value</code></a> runtimes it builds on.

docs/language/tiled/tiled-read.md

@@ -0,0 +1,14 @@
+---
+id: tiled-read
+name: Tiled.read
+category: tiled
+kind: namespace-method
+tokens: Tiled.read
+sig: Tiled.read(path: string) -> value
+tip: Read a map file into the intermediate value tree.
+order: 1
+ns: Tiled
+member: read
+---
+
+Reads a Tiled map file at <code>path</code> — auto-detecting TMX (XML) vs TMJ (JSON) by its first byte — and returns the intermediate map <a href="value"><code>Value</code></a> tree in Tiled's JSON schema: <code>orientation</code>, <code>width</code>/<code>height</code>, <code>tilewidth</code>/<code>tileheight</code>, a <code>tilesets</code> list and a <code>layers</code> list. Every tile layer's <code>data</code> is decoded to a dense GID int list (CSV split, or base64 → zlib/gzip inflate → little-endian u32s), so the two formats yield structurally identical trees.

docs/language/tiled/tiled-read_tsx.md

@@ -0,0 +1,14 @@
+---
+id: tiled-read_tsx
+name: Tiled.read_tsx
+category: tiled
+kind: namespace-method
+tokens: Tiled.read_tsx
+sig: Tiled.read_tsx(path: string) -> value
+tip: Read a tileset file into a value object.
+order: 2
+ns: Tiled
+member: read_tsx
+---
+
+Reads a standalone Tiled tileset file at <code>path</code> (TSX or TSJ) and returns a tileset <a href="value"><code>Value</code></a> object: <code>name</code>, <code>tilewidth</code>/<code>tileheight</code>, <code>spacing</code>, <code>margin</code>, <code>columns</code>, <code>tilecount</code>, the <code>image</code> and its size, and a <code>tiles</code> list of per-tile metadata (animation frames, collision shapes, properties). This is what a map's external <code>{firstgid, source}</code> tileset reference resolves to.