refactor(api)!: one namespace per feature, screen split out

Namespaces were shared across features: `settings` was written by core, the
panel and touch, and `input` by touch and buttons. That made "does this
firmware implement the whole feature?" a question no pointer could answer.

Each namespace now belongs to exactly one feature or to core, so a feature is
a provider pointer and the compiler validates completeness:

  gui, node       -> screen, tree, under the screen feature
  settings        -> screen (rotation, theme), sys (timezone),
                     touch (calibration)
  input           -> touch, buttons

Runtime::open() no longer requires a GuiProvider; a firmware without one runs
with no screen/tree globals and reports sys.hasFeature("screen") false.
Rotation is one value again: GuiProvider::setRotation applies and persists, so
an app rotating the panel transiently puts the old value back itself.

lua/api/features/touch.lua

@@ -2,8 +2,22 @@
 
 -- Generated from native/src/bindings/features/touch.cpp. Do not edit.
 
----@class SettingsLib
-settings = settings or {}
+---@class TouchLib
+touch = {}
+
+---Returns the calibrated touch point, or nothing when the panel is not touched.
+---@return integer? x
+---@return integer? y
+function touch.getPoint() end
+
+---Returns the uncalibrated touch reading, or nothing when the panel is not touched.
+---@return integer? x
+---@return integer? y
+function touch.getRawPoint() end
+
+---Whether the panel is currently touched.
+---@return boolean
+function touch.isTouched() end
 
 ---Persists the panel's touch calibration.
 ---@param x0 integer Raw reading at the left edge.
@@ -12,24 +26,7 @@ settings = settings or {}
 ---@param y1 integer Raw reading at the bottom edge.
 ---@return true? ok
 ---@return string? error
-function settings.setCalibration(x0, y0, x1, y1) end
-
----@class InputLib
-input = input or {}
-
----Returns the calibrated touch point, or nothing when the panel is not touched.
----@return integer? x
----@return integer? y
-function input.getTouch() end
-
----Returns the uncalibrated touch reading, or nothing when the panel is not touched.
----@return integer? x
----@return integer? y
-function input.getRawTouch() end
-
----Whether the panel is currently touched.
----@return boolean
-function input.isTouched() end
+function touch.setCalibration(x0, y0, x1, y1) end
 
 ---Fired when the finger lands.
 ---@param x integer