feat(map-editor): v0.2.0c.2 — palette uses real tile thumbnails

Replaces the placeholder colour swatches with actual atlas sub-tex
draws via the new lib-core.maps 0.5.4 getters:
 - atlas_diffuse_handle(atlas_idx) -> raylib Texture2D handle
 - atlas_tile_uv(atlas_idx, slot)  -> {x, y, w, h} or nil

Renders each slot 1..14 (lib slot 0..13) scaled to fit the swatch
rect with draw_sprite_transform. Falls back to the legacy colour
square + slot-number label when the atlas isn't loaded (headless,
material missing, etc.).

Drives off state.get_active_atlas() (defaults to 0 — fine for the
single-atlas work map; multi-atlas selector is a future slice).

Also bumps lib-core.maps dep 0.5.3 -> 0.5.4.

init.lua

@@ -1,4 +1,4 @@
--- sporel-module-map-editor v0.2.0c.1
+-- sporel-module-map-editor v0.2.0c.2
 -- Interactive map editor — Rev 4 UX architecture (see design paper
 -- 2026-05-28-autotile-blob-styles-design.md §11 + plan stub
 -- 2026-05-28-map-editor-blob-v2.md). 0.2.0b adds the bottom palette
@@ -15,6 +15,9 @@
 -- 0.2.0c.1 adds drag-paint: LMB-hold strokes a line of paints, RMB-hold
 -- a line of erases (both in Auto-Tile and Direct mode). UI clicks on
 -- toolbar / palette / side-panel never enter drag-mode.
+-- 0.2.0c.2 makes the palette show real tile thumbnails via the new
+-- lib-core.maps 0.5.4 atlas-handle / tile-UV getters. Falls back to
+-- the legacy colour swatch when atlas isn't loaded.
 -- Decal/Entity sub-selectors + Material-Properties modal land in 0.2.0d.
 --
 -- All editor logic in this single file: engine sandbox only allows
@@ -626,20 +629,42 @@ local ui = (function()
         engine.render.draw_text("Palette  (slot 1-14)", p.x + 6, p.y + 4, 11,
             rgba(COL_TEXT_MUTED, 0xFF))
 
+        -- 0.2.0c.2: real tile thumbnails via maps.atlas_tile_uv. Atlas
+        -- index 0 (single-atlas maps); falls back to the colour swatch
+        -- if the atlas / tile UV / texture isn't available.
+        local atlas_idx = state.get_active_atlas()
+        local tex = maps.atlas_diffuse_handle(atlas_idx)
+
         local selected_slot = state.get_active_tile()
         for _, sw in ipairs(palette_swatches_layout()) do
             local is_selected = (sw.slot_id == selected_slot)
             local is_hover    = in_rect(mx, my, sw.x, sw.y, sw.w, sw.h)
-            -- Swatch body in the per-slot color.
+            -- Always draw a dark BG so transparent atlas tiles read.
+            engine.render.draw_rect(sw.x, sw.y, sw.w, sw.h, rgba(0x282830, 0xFF))
+            -- Tile thumbnail: scale the atlas sub-tex to fit the swatch.
+            local uv = tex and maps.atlas_tile_uv(atlas_idx, sw.slot_id - 1)
+            if tex and uv then
+                local scale_x = sw.w / uv.w
+                local scale_y = sw.h / uv.h
+                engine.render.draw_sprite_transform(
+                    tex,
+                    sw.x + sw.w / 2, sw.y + sw.h / 2,
+                    0, scale_x, scale_y,
+                    uv.w / 2, uv.h / 2,
+                    0xFFFFFFFF,
+                    uv.x, uv.y, uv.w, uv.h
+                )
+            else
+                -- Fallback: legacy coloured placeholder.
                 engine.render.draw_rect(sw.x, sw.y, sw.w, sw.h,
                     rgba(SWATCH_COLORS[sw.slot_id] or 0x808080, 0xFF))
-            -- Border: highlighted gold when selected, dim when not.
+            end
+            -- Border + label on top.
             local border_col = is_selected and COL_SWATCH_SELECTED
                 or is_hover and COL_TEXT
                 or COL_SWATCH_BORDER
             engine.render.draw_rect_lines(sw.x, sw.y, sw.w, sw.h,
                 rgba(border_col, 0xFF))
-            -- Slot number label in the corner.
             engine.render.draw_text(tostring(sw.slot_id), sw.x + 4, sw.y + 4, 11,
                 rgba(COL_TEXT, 0xE0))
         end
@@ -826,7 +851,7 @@ input.bind("toggle_cheatsheet", { "i" })     -- 0.2.0a — `i` for Info/help (no
 input.bind("flip",              { "h" })     -- 0.2.0c
 input.bind("reset_transform",   { "0" })     -- 0.2.0c
 
-engine.print("map-editor v0.2.0c.1: ready. Tab=mode, I=help, S=save, E=erase, R=rotate, H=flip, 0=reset, ESC=quit")
+engine.print("map-editor v0.2.0c.2: ready. Tab=mode, I=help, S=save, E=erase, R=rotate, H=flip, 0=reset, ESC=quit")
 
 -- =====================================================================
 -- Frame hooks

manifest.module

@@ -1,6 +1,6 @@
 {
     "id": "map-editor",
-    "version": "0.2.0c.1",
+    "version": "0.2.0c.2",
     "kind": "module",
     "api": "^0.1",
     "ci_frames": 30,
@@ -9,7 +9,7 @@
         "blob_rect_stone": "lib-asset.prototype-blob-geom"
     },
     "deps": [
-        {"id":"lib-core.maps","version":"0.5.3"},
+        {"id":"lib-core.maps","version":"0.5.4"},
         {"id":"lib-core.render","version":"0.1.0"},
         {"id":"lib-core.camera","version":"0.3.0"},
         {"id":"lib-core.input","version":"0.4.0"},