Rework the UI on Crusenho's pack; credit it in the game, not just the repo

Crusenho's Complete UI Essential Pack is CC BY 4.0 -- redistributable and
commercial-friendly, confirmed from the License.txt the pack itself ships --
so unlike the two bdragon packs a subset is committed: twelve PNGs, 48 KB,
under assets/sprites/ui/. Only what is used, because each committed PNG costs
a Godot .import sidecar and a directory nothing references is one nobody
prunes.

UiTheme builds a Theme in code from it -- button states, panels, line edits --
and every screen roots itself through UiTheme.themed_root(). The HUD's bars are
the pack's frame with a tinted fill, drawn as three horizontal slices because
Godot's nine-patch lives on nodes and the HUD is drawn rather than built from
controls. Inventory slots use the pack's slot art at exactly twice the source
size; a non-integer scale on a 1px border reads as a wobble along every edge.

The credits screen is the other half of the request and it is a licence
obligation, not a nicety: two packs are now CC BY, which asks for attribution
"in any reasonable manner", and a markdown file in a source repo is not
reasonable for someone who downloaded a build. Settings -> Credits shows every
source with its terms and a link to the licence text. test_credits.gd asserts
CREDITS.md and docs/ASSETS.md name every entry, so the three cannot drift.

Two things found by actually looking at the screen, which is the point:

  - The FIRST version of this styled nothing. A Control inherits its theme from
    Control ANCESTORS only, and the chain breaks at the first plain Node or
    CanvasLayer -- which is every screen here. get_window().theme set the
    property, changed nothing, and read as correct. check.sh, 458 tests and a
    clean smoke run all passed with the entire interface unstyled. The theme
    test now instantiates every screen and asks what its buttons resolve.
  - The settings screen showed Fire bound to the right mouse button, because
    the test suite was writing the player's real user://settings.cfg --
    rebinding calls save() and nothing had redirected the path. Settings.path
    is now redirectable, the fixture points it at a scratch file, and a test
    asserts the default is still the player's own.

tools/screenshot.tscn is what found both. It boots the client windowed and
saves the menus, the HUD, settings and credits. Manual, needs a display, and
the only thing in the project that can tell you the interface rendered.

check.sh clean, 460 tests, SMOKE PASS, all four diagnostics green.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

docs/ASSETS.md

@@ -12,22 +12,24 @@ can be referenced from a scene or script. Files are copied into `res://assets/`
 in game-ready form, and only then imported. The tree is 3.9 GB and
 `tools/check.sh` runs `--import`, which would otherwise walk all of it every run.
 
-What is in the game today totals **548 KB** across seven files: three sprite
-sheets and four sounds. Sprite rects and sound paths are all declared in one
+What is in the game today is three sprite sheets, four sounds and twelve small
+UI sprites. Sprite rects and sound paths are all declared in one
 place, [src/view/art.gd](../src/view/art.gd), and
 `tests/unit/test_art.gd` asserts every rect lands inside its texture — a wrong
 atlas coordinate does not error, it silently draws the wrong pixels.
 
 ## Licence findings
 
-Checked against each pack's itch.io page. **Two of the four forbid
-redistribution**, which is what publishing a repository containing them would
-be — so they are not in the repository.
+Checked against each pack's itch.io page, and against the licence file the pack
+itself ships where there is one. **Two of the five forbid redistribution**,
+which is what publishing a repository containing them would be — so they are not
+in the repository.
 
 | Pack | Licence | Commercial | Credit | In this repo? |
 | --- | --- | --- | --- | --- |
 | [0x72 DungeonTileset II](https://0x72.itch.io/dungeontileset-ii) | **CC0 1.0** (public domain) | Yes | Not required | **Yes** — `assets/sprites/dungeon_tileset.png` |
 | [Helton Yan Pixel Combat](https://heltonyan.itch.io/pixelcombat) | **CC BY 4.0** | Yes | **Required** | **Yes** — `assets/audio/sfx/` |
+| [Complete UI Essential Pack](https://crusenho.itch.io/complete-ui-essential-pack) | **CC BY 4.0** | Yes | **Required** | **Yes** — `assets/sprites/ui/` |
 | [Fire Pixel Bullet 16x16](https://bdragon1727.itch.io/fire-pixel-bullet-16x16) | Custom | Free tier non-commercial; **paid tier allows commercial** | Encouraged | **No, at any tier** — local only |
 | [750+ Effect and FX Pixel All](https://bdragon1727.itch.io/750-effect-and-fx-pixel-all) | Custom | Free tier non-commercial; **paid tier allows commercial** | Encouraged | **No, at any tier** — local only |
 
@@ -56,12 +58,30 @@ passes 156/156 and the game runs.
 This is also why nothing there may be `preload()`ed — `preload` resolves at
 compile time and would fail the build on every machine that lacks the files.
 
+### The UI pack is the easy case
+
+Crusenho's *Complete UI Essential Pack* ships its own `License.txt` naming
+CC BY 4.0 outright, with the licensor and store link spelled out. That permits
+redistribution and commercial use, so unlike the bullet and FX packs a subset of
+it is committed — twelve PNGs, 48 KB, under `assets/sprites/ui/`, listed in
+`UiTheme.TEXTURES`.
+
+Only what the game uses was copied rather than all 98 sprites: each committed
+PNG costs a Godot `.import` sidecar, and a directory of files nothing references
+is a directory nobody prunes. The rest stays in the untracked pack.
+
+The obligation it creates is the same one the audio creates — see below.
+
 ### Two obligations this creates
 
-1. **Helton Yan's CC BY 4.0 requires attribution**, and it is not satisfied by
-   a file in the source tree once the game ships. Players need to be able to
-   see it. [CREDITS.md](../CREDITS.md) records it for now; an in-game credits
-   screen is a todo.
+1. **Two packs are CC BY 4.0 and require attribution** — Helton Yan's audio and
+   Crusenho's UI art. A file in the source tree does not satisfy that once the
+   game ships, because a player who downloaded a build never sees it. **Done:**
+   Settings → Credits shows the same list, built from
+   [src/core/credits.gd](../src/core/credits.gd), including a link to the
+   licence text as CC BY asks. `tests/unit/test_credits.gd` asserts every source
+   there also appears in [CREDITS.md](../CREDITS.md) and in this file, so the
+   three cannot drift apart.
 2. **Both bdragon packs are non-commercial in their free tier.** Buying the
    full tier *does* fix that — confirmed verbatim from the FX pack's paid
    licence: "You may use these assets in personal, commercial or

docs/ROADMAP.md

@@ -20,13 +20,17 @@ What "everything passes" currently means. Numbers move; the shape does not.
 | Gate | Covers | Runtime |
 | --- | --- | --- |
 | `tools/check.sh` | every script parses and type-checks | ~5s |
-| `tools/test.sh` | 439 GUT tests, no SceneTree | ~4s |
+| `tools/test.sh` | 460 GUT tests, no SceneTree | ~4s |
 | `tools/smoke.sh` | 23 assertions over a real ENet socket: handshake, auth, character creation and persistence, both dungeon kinds, escape, hard kill, polite disconnect | ~40s |
 | `diag_prediction.tscn` | client-prediction gap, with injected clock drift | ~10s |
 | `diag_progression.tscn` | kill → xp → level → health, death → retire → roster, swap guards | ~10s |
 | `diag_loot.tscn` | drop → snapshot → pick up → persist → use → drop, and both loot visibilities on the wire | ~10s |
 | `diag_upgrades.tscn` | level → banked choice → refused in a dungeon and away from the NPC → taken → new stats → persisted → **survives every zone change** | ~10s |
 
+`tools/screenshot.tscn` is a **manual** check, not a gate: it needs a display,
+and it is the only thing in the project that can tell you the interface
+actually rendered. Run it after touching `src/ui/`.
+
 The four diagnostics exist because the smoke test structurally cannot reach
 what they cover: bots are poor shots (so they neither level up, produce drops,
 nor walk to the quartermaster), and a listen server cannot drift its own clock
@@ -129,8 +133,10 @@ play off server events. Enough to prove the pipeline, not a finished look.
 | Impact/death VFX animation | todo | `Art.IMPACT` is loaded and validated but nothing plays it yet |
 | Directional sprites, hit flashes, screen shake | todo | |
 | Rebindable controls | done | [src/ui/settings_screen.gd](../src/ui/settings_screen.gd), [src/core/settings.gd](../src/core/settings.gd) |
+| Themed controls from a UI pack | done | [src/view/ui_theme.gd](../src/view/ui_theme.gd), art in `assets/sprites/ui/` |
+| Textured HUD bars and inventory slots | done | `HUD._bar`, `HUD._draw_inventory` |
 | Audio buses and a volume setting | done | `Settings`, an SFX bus created at runtime, sliders in the settings screen |
-| **In-game credits screen** | **todo** | Not cosmetic: the SFX are CC BY 4.0 and attribution is a licence *requirement*. [CREDITS.md](../CREDITS.md) is not reachable by a player. |
+| **In-game credits screen** | **done** | Settings → Credits, from [src/core/credits.gd](../src/core/credits.gd). Two packs are CC BY 4.0 and attribution is a licence *requirement* — [CREDITS.md](../CREDITS.md) is not reachable by a player. |
 | Replace the two non-redistributable packs | todo | Bullet and FX art is local-only and non-commercial. CC0 replacements would let them into the repo and unblock a commercial release. See [ASSETS.md](ASSETS.md). |
 
 ## Stage 2 — Characters, persistence, levels · *done*

docs/WORKFLOW.md

@@ -251,3 +251,24 @@ the output, which is worth doing after any change to startup.
 `smoke.sh` now asserts no plain engine errors either, excluding by name the one
 line Godot prints on every clean exit — naming it means anything else that turns
 up is a real finding rather than noise to be squinted past.
+
+### Nothing automated can see the screen
+
+Every gate passed — 458 tests, a clean smoke run, no engine errors — while the
+entire interface rendered in Godot's default style and none of the UI pack was
+visible. A Control inherits its theme from Control *ancestors only*, and the
+chain breaks at the first plain `Node` or `CanvasLayer`; every screen in this
+game hangs off one. `get_window().theme = ...` set the property, changed
+nothing, and looked correct in the code.
+
+It took `tools/screenshot.tscn` — boot the client, save a PNG, open it — to
+find. The same run then showed **Fire bound to the right mouse button**, which
+was the test suite writing the player's real `user://settings.cfg`, because
+rebinding calls `save()` and nothing had redirected the path.
+
+Two lessons, and the second is the general one:
+
+- After touching `src/ui/`, look at it. There is no substitute.
+- A test that exercises a code path which writes to user state **will write to
+  user state**. Redirect the path in the fixture, and assert the default is
+  still the real one so the redirect cannot escape.