Floating polish: visibility, resize, saved geometry, D-Bus, desktop entry

- VisibilityController: show on field focus, dismiss until next focus,
  manual show/hide/toggle overrides
- FloatingWindow: resize from the corner grip, clamp to screen
- WindowSettings: geometry per screen, debounced saves
- DBusControl: org.sloposk.Keyboard Show/Hide/Toggle for global shortcuts
- org.sloposk.keyboard.desktop so System Settings lists it as a virtual keyboard
- README with build/run/layout docs

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

README.md

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+# sloposk
+
+iPad-style floating on-screen keyboard for Plasma Wayland. Qt 6, C++ core, QML UI.
+
+- Flick a key down for its secondary symbol; long-press for accented alternates
+- iOS shift: tap = one letter, double-tap = caps lock, hold = shift while held
+- Auto-capitalization, double-space → ". ", backspace repeat → word delete
+- Long-press space = trackpad; slide from `.?123` onto a symbol and release
+- Floating: drag the bottom bar, resize from the corner; geometry is remembered per screen
+
+## Build & test
+
+```sh
+cmake -B build -G Ninja && cmake --build build
+ctest --test-dir build
+```
+
+Needs Qt ≥ 6.8 (Quick, WaylandClient, DBus, Test), LayerShellQt, xkbcommon, wayland-protocols.
+
+## Run
+
+KWin only offers the input-method protocol to the process it launches itself.
+
+| Where | How |
+|---|---|
+| Nested session (safe) | `kwin_wayland --no-lockscreen --socket sloposk-dev --width 1400 --height 900 --inputmethod $PWD/build/src/sloposk kwrite` |
+| Desktop | `cmake --install build --prefix ~/.local`, then System Settings → Keyboard → Virtual Keyboard → **sloposk** |
+| UI only | `build/src/sloposk` (stays visible, types nowhere) |
+
+Show/hide, e.g. from a global shortcut: `qdbus org.sloposk.Keyboard /Keyboard org.sloposk.Keyboard.Toggle`
+
+Dev hooks: `SLOPOSK_AUTOTYPE=text` commits on focus; `SLOPOSK_SCREENSHOT=file.png` saves the window and quits.
+
+## Layouts
+
+JSON in `layouts/` (built in) or `~/.local/share/sloposk/layouts/` (overrides by `id`). The globe key cycles them; the system locale's comes first.
+
+```json
+{
+  "id": "sv-SE", "name": "Svenska", "locale": "sv_SE",
+  "base": "en-US",
+  "layers": [{"name": "letters", "rows": [[
+    "q",
+    {"label": "e", "flick": "3", "alternates": ["é", "è"]},
+    {"type": "backspace", "width": 1.5}
+  ]]}]
+}
+```
+
+- Key: a string, or an object with `type` (`char` `space` `backspace` `enter` `shift` `layer` `globe` `dismiss` `spacer`), `label`, `shifted`, `flick`, `alternates`, `width` (key units), `target` (for `layer`)
+- `base`: take layers this layout doesn't define (e.g. numbers/symbols) from another layout
+- Rows in a layer should add up to the same width; `tst_layoutloader` checks the built-ins
+
+## Architecture
+
+```
+qml/        view only
+input/      touch → PointerTracker gestures → KeyboardController rules
+engine/     key output → text ops (DirectEngine; prediction/swipe later)
+backend/    text ops → compositor (KWin input-method-v1)
+layout/     JSON → Layout → LayoutModel (geometry, hit testing)
+window/     floating layer-shell placement, visibility, saved geometry
+app/        D-Bus control, dev hooks
+```
+
+`sloposk_core` (everything compositor-independent, plus the `Sloposk` QML module) is a static library shared by the app and the tests.