feat(x11): add XDrawer global phone controls drawer, softkey chord detection, and st/T9 scrollback

MANUAL.md

@@ -105,6 +105,7 @@ sudo dd if=./images/bananarchy-nokia-argon.img of=/dev/sdX bs=4M status=progress
 | :--- | :--- | :--- |
 | **Left softkey** | `XF86KbdLcdMenu1` (`KEY_MENU`) | Open **System menu**, close open menu, or wake & unlock when locked |
 | **Right softkey / Back** | `XF86KbdLcdMenu2` / `BackSpace` (`KEY_BACK`) | Open **App context menu** (or close menu if open); in apps/T9 preedit acts as `BackSpace` |
+| **Both softkeys together** | `KEY_MENU` + `KEY_BACK` | Toggle **`XDrawer`** (`xdrawer`) global phone controls overlay (Speaker, Earpiece, Flashlight, Sound, Microphone, Screen, Keypad) from anywhere |
 | **Call (green)** | `XF86PickupPhone` (`KEY_SEND`) | Wake & unlock when locked, confirm (`Return`) in menus, or: **1×** answer call / **App context menu**, **2×** **Focus next window**, **3×** **Toggle tiling layout** (`vertical` -> `horizontal` -> `tabbed`) |
 | **End / Power (red)** | `XF86PowerOff` | Wake & unlock when locked, close open menu, or: **1×** **Power menu** (`space` shutter in Megapixels), **2×** cycle screen state, **3×** (or hold `400ms`) launch new terminal |
 | **D-Pad up / down** | `Up` / `Down` | Navigate menus/apps; in T9 preedit: toggle letter case (`a` ↔ `A`) or jump `+4` / `-4` candidates; in idle `Ctl` mode: `Page_Up` / `Page_Down` |
@@ -199,7 +200,7 @@ You can switch between **vertical stack (`TTT`, `bstack`)**, **horizontal tile (
 | **`4`** | `^R` `^L` `^P` `^N` `^G` |
 | **`5`** | `^S` `^Q` `^O` `^T` `^Y` |
 | **`6`** | `^B` `^F` `^V` `^H` `^[` `^]` `^^` `^_` |
-| **`7`** | `PgUp` `PgDn` `Home` `End` |
+| **`7`** | `PgUp` `PgDn` `Home` `End` `ScrlUp` `ScrlDn` |
 | **`8`** | `Up` `Down` `Left` `Right` |
 | **`9`** | `F1` `F2` `F3` `F4` `F5` `F6` `F7` `F8` `F9` `F10` `F11` `F12` |
 | **`0`** | `Space` (`SPC`) `Tab` `Ent` (`Return`) `Esc` |