feat: add fixed board scaling

apps/docs/docs/management/api/index.mdx

@@ -62,6 +62,11 @@ Each board has exactly one Mobile and one Base layout. Mobile uses breakpoint `0
 layouts can use any other breakpoint, and Homarr selects the highest breakpoint that fits the viewport. Preserve layout
 roles and use the canonical layouts returned by save operations, including generated IDs.
 
+Board settings expose `fixedScaling` and `fixedItemSize`. The default fitted mode uses `fixedScaling: false`; setting it
+to `true` keeps each `1 × 1` tile at `fixedItemSize` pixels, which must be an integer from `100` through `400`. The
+configured size is retained while fixed scaling is disabled. Layout `columnCount` remains the maximum total column count,
+including fixed sidebars.
+
 Creating or changing an integration-backed widget requires use access to each newly selected integration.
 
 ## Docker targets

apps/docs/docs/management/boards/index.mdx

@@ -27,9 +27,13 @@ Mobile and Base are protected layouts. New boards use three Mobile columns; Base
 creation. Additional layouts use unique breakpoints. Homarr selects the layout with the highest breakpoint that fits
 the current viewport.
 
-Tiles use fixed `200 × 200` logical-pixel cells with a `24px` gap. Homarr scales the complete layout to the available
-width instead of changing each widget's proportions. **Reset from Base** regenerates a Mobile or custom layout from the
-current Base layout.
+By default, Homarr fits the complete fixed-proportion tile grid to the available width. Enable **Fixed scaling** in the
+board's Layout settings to render every `1 × 1` tile at the exact configured pixel size instead. A fixed dashboard is
+centred when it fits and scrolls both horizontally and vertically when it does not.
+
+The column count is the maximum total for that layout, including any fixed sidebars. For example, a Base layout with
+five columns and no sidebars remains a centred five-column dashboard on an ultrawide screen. **Reset from Base**
+regenerates a Mobile or custom layout from the current Base layout.
 
 ### Containers and rails
 
@@ -59,7 +63,7 @@ click remains available as a shortcut.
 Board settings cover:
 
 - **General:** page title, browser title, logo, and favicon.
-- **Layout:** responsive layouts, breakpoints, columns, and rails.
+- **Layout:** fitted or fixed scaling, tile size, responsive layouts, breakpoints, maximum columns, and rails.
 - **Background:** image, attachment, size, and repeat behavior.
 - **Appearance:** colors, opacity, icon color, and item radius.
 - **Custom CSS:** styles applied only to the current board.

apps/docs/static/api/open-api-schema.json

@@ -2151,6 +2151,14 @@
                       }
                     ]
                   },
+                  "fixedScaling": {
+                    "type": "boolean"
+                  },
+                  "fixedItemSize": {
+                    "type": "integer",
+                    "minimum": 100,
+                    "maximum": 400
+                  },
                   "disableStatus": {
                     "type": "boolean"
                   }