feat(lid-guard): add lid-close suspension inhibitor (#30)

* feat(lid-guard): add lid-close suspension inhibitor

* docs(lid-guard): replace plugin thumbnail

lid-guard/README.md

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+# Lid Guard
+
+Lid Guard keeps a laptop awake when its lid is closed, allowing AI agents,
+builds, downloads, and other background jobs to continue without changing the
+system-wide lid policy.
+
+## Plugin
+
+| Field | Value |
+| --- | --- |
+| ID | `8bury/lid-guard` |
+| Entries | Bar widget: `lid-guard`; shortcut: `lid-guard-toggle`; service: `lid-guard-service` |
+
+## Requirements
+
+Install `systemctl`, `systemd-run`, and `systemd-inhibit` from systemd, plus
+`sleep` from coreutils, on `PATH`. The active user session must use
+`systemd-logind` and have a working user service manager.
+
+## Usage
+
+Add the `lid-guard` widget to a bar. Left-click the shield to toggle the mode;
+right-click it to refresh the detected state. A highlighted shield means the
+lid-close inhibitor is active.
+
+To use the same toggle from the Control Center, add the `lid-guard-toggle`
+shortcut in Settings → Control Center → Shortcuts.
+
+The service entry `lid-guard-service` owns the inhibitor and can also be
+controlled through IPC:
+
+```sh
+noctalia msg plugin 8bury/lid-guard:lid-guard-service all enable
+noctalia msg plugin 8bury/lid-guard:lid-guard-service all disable
+noctalia msg plugin 8bury/lid-guard:lid-guard-service all toggle
+noctalia msg plugin 8bury/lid-guard:lid-guard-service all refresh
+```
+
+## IPC
+
+The `enable`, `disable`, and `toggle` events change the inhibitor state.
+`refresh` and `status` re-check the transient user service without changing it.
+IPC events take no payload.
+
+## Notes
+
+Lid Guard makes no network requests and writes no files. It spawns
+`systemctl`, `systemd-run`, `systemd-inhibit`, and `sleep` as the current user.
+When enabled, it creates the transient user service
+`noctalia-lid-guard.service`; disabling the mode stops that service.
+
+The inhibitor covers only `handle-lid-switch`. It does not prevent suspension
+requested by an idle daemon, a power menu, or another explicit command, and it
+does not modify `logind.conf`. The mode ends when the user session or user
+service manager stops. If Noctalia is unavailable, restore the normal lid
+behavior with:
+
+```sh
+systemctl --user stop noctalia-lid-guard.service
+```

lid-guard/plugin.toml

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+id = "8bury/lid-guard"
+name = "Lid Guard"
+version = "1.0.0"
+plugin_api = 3
+author = "8bury"
+license = "MIT"
+icon = "shield-lock"
+description = "Keep the laptop awake when its lid is closed, so background jobs can continue running."
+tags = ["bar", "indicator", "productivity", "service", "shortcut", "system", "utility"]
+dependencies = ["systemctl", "systemd-run", "systemd-inhibit", "sleep"]
+
+[[service]]
+id = "lid-guard-service"
+entry = "service.luau"
+
+[[widget]]
+id = "lid-guard"
+entry = "widget.luau"
+
+[[shortcut]]
+id = "lid-guard-toggle"
+entry = "shortcut.luau"

lid-guard/service.luau

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+--!nonstrict
+-- Owns the systemd inhibitor. Widgets and shortcuts communicate with this
+-- singleton through noctalia.state.
+
+local UNIT = "noctalia-lid-guard.service"
+local CHECK_COMMAND = `systemctl --user is-active --quiet {UNIT}`
+local START_COMMAND = `systemctl --user reset-failed {UNIT} >/dev/null 2>&1 || true; ` .. table.concat({
+  `systemd-run --user --quiet --collect --unit={UNIT}`,
+  `--description='Noctalia Lid Guard'`,
+  `systemd-inhibit --what=handle-lid-switch`,
+  `--who='Noctalia Lid Guard'`,
+  `--why='Keep background jobs running while the laptop lid is closed'`,
+  `--mode=block sleep infinity`,
+}, " ")
+local STOP_COMMAND = `systemctl --user stop {UNIT}`
+
+local active = false
+local busy = false
+local available = noctalia.commandExists("systemctl")
+  and noctalia.commandExists("systemd-run")
+  and noctalia.commandExists("systemd-inhibit")
+  and noctalia.commandExists("sleep")
+local revision = 0
+
+local function publish(errorMessage)
+  revision += 1
+  noctalia.state.set("lid_guard_status", {
+    active = active,
+    busy = busy,
+    available = available,
+    error = errorMessage or "",
+    revision = revision,
+  })
+end
+
+local function refresh(callback)
+  if not available then
+    active = false
+    publish(noctalia.tr("error.missing_dependencies"))
+    if callback then callback(false) end
+    return
+  end
+
+  noctalia.runAsync(CHECK_COMMAND, function(result)
+    active = result.exitCode == 0
+    publish()
+    if callback then callback(active) end
+  end)
+end
+
+local function finishToggle(expectedActive, result)
+  if result.exitCode ~= 0 then
+    busy = false
+    local detail = noctalia.string.trim(result.stderr or "")
+    if detail == "" then detail = noctalia.tr("error.command_failed") end
+    publish(detail)
+    noctalia.notifyError(noctalia.tr("title"), detail)
+    return
+  end
+
+  refresh(function(currentActive)
+    busy = false
+    active = currentActive
+    publish()
+
+    if currentActive ~= expectedActive then
+      noctalia.notifyError(noctalia.tr("title"), noctalia.tr("error.state_mismatch"))
+    elseif currentActive then
+      noctalia.notify(noctalia.tr("notification.enabled.title"), noctalia.tr("notification.enabled.body"))
+    else
+      noctalia.notify(noctalia.tr("notification.disabled.title"), noctalia.tr("notification.disabled.body"))
+    end
+  end)
+end
+
+local function setActive(nextActive)
+  if busy or not available then return end
+  busy = true
+  publish()
+
+  if nextActive then
+    noctalia.runAsync(START_COMMAND, function(result)
+      finishToggle(true, result)
+    end)
+  else
+    noctalia.runAsync(STOP_COMMAND, function(result)
+      finishToggle(false, result)
+    end)
+  end
+end
+
+noctalia.state.watch("lid_guard_command", function(command)
+  if type(command) ~= "table" then return end
+
+  if command.action == "toggle" then
+    refresh(function(currentActive)
+      setActive(not currentActive)
+    end)
+  elseif command.action == "enable" then
+    setActive(true)
+  elseif command.action == "disable" then
+    setActive(false)
+  elseif command.action == "refresh" then
+    refresh()
+  end
+end)
+
+noctalia.setUpdateInterval(5000)
+refresh()
+
+function update()
+  if not busy then refresh() end
+end
+
+function onIpc(event, _payload)
+  if event == "toggle" then
+    refresh(function(currentActive)
+      setActive(not currentActive)
+    end)
+  elseif event == "enable" then
+    setActive(true)
+  elseif event == "disable" then
+    setActive(false)
+  elseif event == "refresh" or event == "status" then
+    refresh()
+  end
+end

lid-guard/shortcut.luau

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+--!nonstrict
+
+local status = noctalia.state.get("lid_guard_status") or {
+  active = false,
+  busy = false,
+  available = true,
+}
+local requestId = 0
+
+local function render()
+  local active = status.active == true
+  shortcut.setLabel(if active then noctalia.tr("shortcut.active") else noctalia.tr("shortcut.inactive"))
+  shortcut.setIcon("shield-lock", "shield-off")
+  shortcut.setActive(active)
+  shortcut.setEnabled(status.available ~= false and status.busy ~= true)
+end
+
+noctalia.state.watch("lid_guard_status", function(value)
+  if type(value) == "table" then
+    status = value
+    render()
+  end
+end)
+
+render()
+
+function onClick()
+  if status.available == false or status.busy == true then return end
+  requestId += 1
+  noctalia.state.set("lid_guard_command", {
+    action = "toggle",
+    requestId = `shortcut-{requestId}`,
+  })
+end

lid-guard/translations/en.json

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+{
+  "title": "Lid Guard",
+  "tooltip": {
+    "active": "Lid Guard is on — closing the lid will not suspend the laptop",
+    "inactive": "Lid Guard is off — click to keep the laptop awake with the lid closed",
+    "changing": "Changing Lid Guard state…",
+    "unavailable": "Lid Guard requires systemd"
+  },
+  "shortcut": {
+    "active": "Lid Guard On",
+    "inactive": "Lid Guard Off"
+  },
+  "notification": {
+    "enabled": {
+      "title": "Lid Guard enabled",
+      "body": "Closing the laptop lid will no longer suspend it."
+    },
+    "disabled": {
+      "title": "Lid Guard disabled",
+      "body": "The normal lid-close behavior has been restored."
+    }
+  },
+  "error": {
+    "missing_dependencies": "systemctl, systemd-run, systemd-inhibit, and sleep are required.",
+    "command_failed": "The systemd command failed.",
+    "state_mismatch": "The requested state could not be confirmed."
+  }
+}

lid-guard/widget.luau

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+--!nonstrict
+
+local status = noctalia.state.get("lid_guard_status") or {
+  active = false,
+  busy = false,
+  available = true,
+}
+local requestId = 0
+
+local function render()
+  if status.available == false then
+    barWidget.setGlyph("shield-x")
+    barWidget.setGlyphColor("error")
+    barWidget.setTooltip(noctalia.tr("tooltip.unavailable"))
+  elseif status.busy == true then
+    barWidget.setGlyph("loader-2")
+    barWidget.setGlyphColor("primary")
+    barWidget.setTooltip(noctalia.tr("tooltip.changing"))
+  elseif status.active == true then
+    barWidget.setGlyph("shield-lock")
+    barWidget.setGlyphColor("tertiary")
+    barWidget.setTooltip(noctalia.tr("tooltip.active"))
+  else
+    barWidget.setGlyph("shield-off")
+    barWidget.setGlyphColor("on_surface_variant")
+    barWidget.setTooltip(noctalia.tr("tooltip.inactive"))
+  end
+end
+
+noctalia.state.watch("lid_guard_status", function(value)
+  if type(value) == "table" then
+    status = value
+    render()
+  end
+end)
+
+render()
+
+function onClick()
+  if status.available == false then
+    noctalia.notifyError(noctalia.tr("title"), status.error or noctalia.tr("error.missing_dependencies"))
+    return
+  end
+  if status.busy == true then return end
+
+  requestId += 1
+  noctalia.state.set("lid_guard_command", {
+    action = "toggle",
+    requestId = `widget-{requestId}`,
+  })
+end
+
+function onRightClick()
+  requestId += 1
+  noctalia.state.set("lid_guard_command", {
+    action = "refresh",
+    requestId = `widget-refresh-{requestId}`,
+  })
+end