feat(status): auto-present while a game runs

Presentation is worth having automatically while a game runs: it is a
fullscreen app that already holds the screen, and the idle lock, DND and
breaktimer are all unwanted during it.

Detection is a 5s poll for a gamescope process or a Steam game binary,
either one enough. The Steam pattern is bracketed so pgrep -f cannot match
the sh running the check and report a game forever.

The result goes to its own status.gaming file, and presentation becomes the
OR of it and status.presentation. That separation is the point: a game
ending clears only the gaming half, so a presentation set by hand survives
a game session instead of being clobbered on exit.

2 files changed, 77 insertions, 2 deletions

diff --git a/desktop/modules/status/README.md b/desktop/modules/status/README.md
index 87654d5..e043dcd 100644
--- a/desktop/modules/status/README.md
+++ b/desktop/modules/status/README.md
@@ -1,13 +1,16 @@
 # status
 
 Desktop modes as state: `dnd`, `presentation` and `nolock`, owned by the
-`Status` singleton and stored as files under `$XDG_RUNTIME_DIR`.
+`Status` singleton and stored as files under `$XDG_RUNTIME_DIR`. A fourth,
+`status.gaming`, is written only by the shell's game detector; it is not a
+mode `statusctl` exposes.
 
 ## The files are the interface
 
     $XDG_RUNTIME_DIR/status.dnd
     $XDG_RUNTIME_DIR/status.presentation
     $XDG_RUNTIME_DIR/status.nolock
+    $XDG_RUNTIME_DIR/status.gaming
 
 Each holds `0` or `1`; a missing file means off. That directory is tmpfs, so a
 reboot resets every mode and there is no cleanup code. A shell restart does
@@ -95,6 +98,29 @@ toward `activeCount`: a running daemon is not a mode the user switched on.
 The daemon's own configuration lives in `~/.config/breaktimer.conf` and is not
 edited from here; `breaktimer.sh config` prints what is in effect.
 
+## Game detection
+
+Presentation is set automatically while a game runs, so a fullscreen game does
+not get locked or interrupted by the idle timer, DND or breaktimer. The shell
+polls every five seconds for a `gamescope` process or a running Steam binary,
+and either one is enough:
+
+    pgrep -x gamescope || pgrep -f 'steamapps/commo[n]'
+
+The steam pattern is bracketed so it cannot match the check's own command
+line: `pgrep -f` reads the whole argv, and a literal `steamapps/common` would
+match the `sh` running the check and report a game forever.
+
+The result is written to `status.gaming`, a file separate from
+`status.presentation`, and presentation is the OR of the two. That separation
+is the point: a game ending clears only the gaming half, so a presentation the
+user set by hand survives for the whole game session instead of being clobbered
+on exit. It also means presentation cannot be turned off by hand while a game
+runs, since `status.gaming` holds it on until the game exits.
+
+`status.gaming` is never set by `statusctl`; the detector owns it. The effects
+are unchanged, because they key off the combined `presentation` value.
+
 ## Waybar
 
 `custom/presentation` reads `statusctl presentation watch`. It replaces
diff --git a/shared/Status.qml b/shared/Status.qml
index dfb6b83..36853af 100644
--- a/shared/Status.qml
+++ b/shared/Status.qml
@@ -31,7 +31,11 @@ Singleton {
     readonly property string dir: Quickshell.env("XDG_RUNTIME_DIR") || "/tmp"
 
     readonly property bool dnd: dndFile.value
-    readonly property bool presentation: presFile.value
+    // Set by the game detector below, on its own file so it never fights the
+    // manual toggle: presentation is the OR, and a game ending clears only its
+    // half. A manual "on" therefore survives a game session.
+    readonly property bool gaming: gamingFile.value
+    readonly property bool presentation: presFile.value || gamingFile.value
     // Stored as "auto-lock disabled", so the missing-file default of off is
     // the wanted default of locking on. The row inverts it for the label.
     readonly property bool nolock: nolockFile.value
@@ -104,6 +108,12 @@ Singleton {
         else if (name === "nolock") root.setMode("nolock", !root.nolock);
     }
 
+    // The detector calls this every poll; a write on an unchanged value would
+    // still land as an atomic write and re-fire the FileView watch for nothing.
+    function setGaming(on) {
+        if (on !== root.gaming) gamingFile.write(on);
+    }
+
     // The timed disable re-enables itself. Runs only while a deadline is
     // pending, so no tick burns while the mode is off or permanently on.
     Timer {
@@ -162,6 +172,43 @@ Singleton {
         }
     }
 
+    // --- game detection ---------------------------------------------------
+    //
+    // A game is a fullscreen app that already holds the screen, and the idle
+    // lock, DND and breaktimer are all unwanted while it runs, so presentation
+    // is set automatically. This machine's games come from Steam and launch
+    // either under gamescope or directly, so both are tested and either one is
+    // enough.
+    //
+    // The steam pattern is bracketed so it cannot match this very command
+    // line: pgrep -f reads the whole argv, and the literal "steamapps/common"
+    // here would otherwise match the sh running the check and report a game
+    // forever. The character class makes the needle miss itself while still
+    // matching a real game path.
+    Process {
+        id: gameProc
+        command: ["sh", "-c",
+            "pgrep -x gamescope >/dev/null 2>&1 || pgrep -f 'steamapps/commo[n]' >/dev/null 2>&1"]
+        onExited: code => root.setGaming(code === 0)
+    }
+
+    // Process lifecycle is not a file to watch, so this polls. A game launch
+    // does not need sub-second latency to present; a missed start corrects on
+    // the next tick. triggeredOnStart covers a shell start while a game is
+    // already up.
+    Timer {
+        interval: 5000
+        repeat: true
+        running: true
+        triggeredOnStart: true
+        onTriggered: {
+            // Re-assigning running on an already-running Process is a no-op,
+            // so it is cleared first.
+            gameProc.running = false;
+            gameProc.running = true;
+        }
+    }
+
     // Wayland idle inhibit. The compositor advertises
     // zwp_idle_inhibit_manager_v1 and hypridle honours it, so no D-Bus path
     // is needed even though elogind runs here. nolock is the sole holder;
@@ -250,6 +297,8 @@ Singleton {
     ModeFile { id: dndFile; path: root.dir + "/status.dnd" }
     ModeFile { id: presFile; path: root.dir + "/status.presentation" }
     ModeFile { id: nolockFile; path: root.dir + "/status.nolock" }
+    // Written only by the game detector above, never by statusctl.
+    ModeFile { id: gamingFile; path: root.dir + "/status.gaming" }
 
     WordFile { id: btStateFile; path: root.dir + "/breaktimer.state" }
     WordFile { id: btPhaseFile; path: root.dir + "/breaktimer.phase" }