Add pulsar-mouse plugin (#318)

* Add pulsar-mouse plugin

Battery/charging status and quick sensor/lighting/power controls for a
Pulsar gaming mouse (bar widget, desktop/lock-screen widget, and a
quick-controls panel), backed by the pulsar-mouse CLI from
https://github.com/harveywuk/pulsar-mouse-linux.

* pulsar-mouse: sync to v1.6.1 (three panel fixes)

The plugin picked up four commits upstream after this PR's initial
snapshot was taken. Three of them are bug fixes, two user-facing enough
that installing the current snapshot gives a visibly broken panel:

- Panel went permanently read-only after a successful profile switch.
  Every control is `enabled = not busy`, and the profile-switch path set
  busy = true then relied on readStatus() to clear it, which it did not
  do on any path. No error was shown, because from the user's point of
  view nothing had failed.

- readStatus() did not guard decoded.dpi being absent, so a malformed
  response threw before clearing busy - the same lockup by another route.

- The panel only re-synced to the mouse's real active profile on the
  first open of the process, because the profileSynced flag is module-
  scoped and survived the panel closing. Switching profiles by any other
  means afterwards (physical profile button, `pulsar-mouse
  --active-profile`, Fusion on another OS) left every later reopen
  showing, and writing to, a stale profile.

The fourth renames "breath" to "breathe" so the LED effect naming
matches the pulsar-mouse CLI's --breathe-speed flag; that accounts for
the two README wording changes and part of the panel diff.

plugin.toml's version goes 1.6.0 -> 1.6.1 per the contribution rules
(patch: fixes and text only, no new capability). Its header comment also
now describes the tabbed panel that shipped earlier rather than the
original DPI/polling-only one.

bar.luau, desktop.luau, translations/en.json and thumbnail.webp are
unchanged and untouched.

No change to what the plugin shells out to, writes, or reads: still only
`pulsar-mouse` (declared in dependencies), still only reading
~/.cache/pulsar-mouse/battery.json. No network access.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

---------

Co-authored-by: Claude Sonnet 5 <noreply@anthropic.com>

pulsar-mouse/translations/en.json

@@ -0,0 +1,44 @@
+{
+  "settings": {
+    "color": {
+      "label": "Color",
+      "description": "Accent color for the percentage text and progress bar"
+    },
+    "show_progress": {
+      "label": "Show Progress Bar"
+    },
+    "show_percent": {
+      "label": "Show Percentage Text",
+      "description": "Turn off to rely on just the glyph (and progress bar, if shown)"
+    },
+    "glyph_size": {
+      "label": "Glyph Size"
+    }
+  },
+  "ui": {
+    "charging": "(charging)",
+    "not-installed": "pulsar-mouse not found",
+    "no-mouse": "Mouse not found",
+    "profile-label": "Profile",
+    "dpi-label": "DPI",
+    "polling-label": "Polling Rate",
+    "led-label": "LED Effect",
+    "brightness-label": "Brightness",
+    "speed-label": "Speed",
+    "write-failed": "Failed to apply - is the mouse connected?",
+    "loading": "Loading...",
+    "wired": "Wired",
+    "signal-label": "Signal",
+    "tab-sensor": "Sensor",
+    "tab-advanced": "Advanced",
+    "tab-lighting": "Lighting",
+    "tab-power": "Power",
+    "debounce-label": "Debounce",
+    "angle-snap-label": "Angle Snap",
+    "ripple-label": "Ripple Control",
+    "motion-sync-label": "Motion Sync",
+    "lod-label": "Lift-off Distance",
+    "power-saving-label": "Wireless Power Saving",
+    "low-power-label": "Low Power Mode"
+  }
+}