fix: backward-compat + bug fixes and man-page build fix for 0.16.0

Post-0.15.0 review of the 0.15.0..HEAD range surfaced regressions and
bugs. This restores backward compatibility for existing configs/CSS,
fixes confirmed defects, and repairs the scdoc man-page build break on
master. Pango-markup tooltips are intentional and were kept.

Backward-compat restorations:
- AModule: honor legacy numeric Gdk::CursorType cursor values (int overload)
- memory: correct GiB divisor (was ~2.3% low); round bare {} placeholders
- wireplumber: scale max-volume into the linear domain so the cap works again
- idle_inhibitor: gate right/middle-click deactivate & scroll on dynamic-timeouts;
  accept both dynamic-timeout(s); widen timeout to double (no fractional truncation)
- custom: keep #custom-<name>.<class> CSS selectors working (classes on box_)
- image: don't wordexp-split a single path; fall back to the literal path
- niri/window: restore hide-when-empty (new show-empty opt-in); escape tooltip
- wlr/taskbar: plain-text tooltip when markup is disabled

Bug fixes:
- tray: fix use-after-free in onAdd; guard the watcher retry timeout
- hyprland: clamp max-windows iterator (OOB); drop duplicate language tooltip block
- niri/window: supply {col}/{max_col} args in the empty branch (fmt::format_error)
- mpris: escape {dynamic}/{player} tooltip; fix dangling player; albumArtist source
- mango: fix use-after-free race (dispatch under callback_mutex_)
- mpd: contain throwing checkErrors in noexcept idle paths (no std::terminate/UAF)
- keyboard_state: always render every lock label, with guarded defaults
- bluetooth: bound GATT ReadValue timeout, opt-in + services-resolved gating,
  preserve authoritative Battery1 percentage
- wireplumber: fix WpDevice reference leak / NULL handling
- battery, clock, dwl, wayfire, graph, custom_graph, transform, river: assorted
  crash/logic fixes

Man page / build:
- niri-workspaces: fix scdoc "indented by an amount greater than 1"
  (workspace-taskbar sub-options were mis-indented; breaks man-page build)
- document new show-empty (niri/window); correct network {txBitrate}/{rxBitrate}

Not compiled locally (no gtkmm on this host); C++ build relies on CI.
Man pages validated with scdoc 1.11.4.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

man/waybar-idle-inhibitor.5.scd

@@ -76,7 +76,7 @@ screensaver, also known as "presentation mode".
 	typeof: double ++
 	The number of minutes the inhibition should last.
 
-*timeout_step*: ++
+*timeout-step*: ++
 	typeof: double ++
 	default: 10 ++
 	The number of minutes to add or subtract when scrolling (when dynamic timeouts are enabled).

man/waybar-network.5.scd

@@ -196,9 +196,9 @@ Addressed by *network*
 
 *{bandwidthTotalBytes}*: Instant total speed in bytes/seconds.
 
-*{tx_bitrate}*: Link transmit bitrate (e.g., 866.7 Mb/s).
+*{txBitrate}*: Link transmit bitrate (e.g., 866.7 Mb/s).
 
-*{rx_bitrate}*: Link receive bitrate (e.g., 866.7 Mb/s).
+*{rxBitrate}*: Link receive bitrate (e.g., 866.7 Mb/s).
 
 *{linkSpeed}*: Ethernet link speed.
 

man/waybar-niri-window.5.scd

@@ -40,6 +40,11 @@ Addressed by *niri/window*
 	default: false ++
 	Enables this module to consume all left over space dynamically.
 
+*show-empty*: ++
+	typeof: bool ++
+	default: false ++
+	When no window is focused (empty workspace or all windows closed), keep the module visible and render *format* with empty {title}/{app_id} and {col}/{max_col} set to -1. When false (the default), the module is hidden while no window is focused.
+
 # FORMAT REPLACEMENTS
 
 See the output of "niri msg windows" for examples

man/waybar-niri-workspaces.5.scd

@@ -96,15 +96,15 @@ If none of the sorting options are enabled, workspaces keep their output/index o
 	typeof: object ++
 	Contains settings for the workspace taskbar, which displays app icons within each workspace.
 
-		*enable*: ++
-	typeof: bool ++
-	default: false ++
-	Enables the workspace taskbar mode.
+	*enable*: ++
+		typeof: bool ++
+		default: false ++
+		Enables the workspace taskbar mode.
 
-		*icon-size*: ++
-	typeof: int ++
-	default: 18 ++
-	Size of the icons in the workspace taskbar.
+	*icon-size*: ++
+		typeof: int ++
+		default: 18 ++
+		Size of the icons in the workspace taskbar.
 
 *ignore-workspaces*: ++
 	typeof: array ++

man/waybar-styles.5.scd.in

@@ -67,6 +67,11 @@ see the cursor-shape-v1 protocol for all possible cursor types:
 https://wayland.app/protocols/cursor-shape-v1#wp_cursor_shape_device_v1:enum:shape.
 Depending on the compositor and cursor theme used, cursors not listed in the protocol may also work.
 
+Prior to 0.16.0 the `cursor` option accepted a numeric _Gdk::CursorType_ value
+(e.g. `"cursor": 8`). Numeric values are deprecated but still honored for
+backward compatibility; a cursor-shape-v1 name string (e.g. `"grab"`) is now
+preferred.
+
 Example of disabling the cursor on a custom module:
 
 ```