Add blank symbol and link-panel pages (#18)

docs/ASSET_PROVENANCE.md

@@ -0,0 +1,15 @@
+# Asset provenance
+
+Rivencraft reuses selected assets from
+[Mystcraft Legacy](https://github.com/Mystcraft/Mystcraft-Legacy) under that
+project's GNU LGPL v3 license. Rivencraft itself uses the same license.
+
+| Rivencraft asset | Upstream asset | Upstream revision | Changes |
+| --- | --- | --- | --- |
+| `assets/rivencraft/textures/item/page.png` | `assets/mystcraft/textures/items/page_background.png` | `9bc8ddc061845df0cd5ea47f4fdef773cff786ae` | Namespace/path rename only |
+| `assets/rivencraft/textures/item/page_link_panel.png` | `page_background.png` and `PageBuilder.BasicPageSprite` | `9bc8ddc061845df0cd5ea47f4fdef773cff786ae` | Reproduces the legacy 160 px scale, black panel at `(25,30)`–`(135,75)`, and 128 px resample |
+| `assets/rivencraft/textures/item/page_symbol*.png` and `page_unresolved.png` | `page_background.png`, `textures/symbolcomponents.png`, `WordData`, `ModSymbols`, and `PageBuilder.PageSprite` | `9bc8ddc061845df0cd5ea47f4fdef773cff786ae` | Static 1.21.1 renditions of the legacy runtime-composed four-word symbol pages; `normal_time` uses the legacy Full Length poem |
+
+Mystcraft Legacy identifies XCompWiz as its project developer and includes the
+full LGPL v3 text in its root `LICENSE` file. Rivencraft's root `LICENSE`
+provides the same license terms.