Add ready-to-use example modules

examples/modules/ ships complete, drop-in bread modules for common desktop
automations (low-battery warning, pause-media-on-headphone-unplug,
dock-monitors) plus a README on installing them. Complements Examples.md,
which teaches the porting patterns.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

examples/modules/low-battery-warning.lua

@@ -0,0 +1,29 @@
+-- low-battery-warning — notify once when the battery runs low.
+--
+-- Drop-in: copy into ~/.config/bread/modules/ (auto-discovered; no init.lua
+-- edit needed). Zero configuration.
+
+local M = bread.module({ name = "low-battery-warning", version = "1.0.0" })
+
+-- Latch so we warn once per low-battery episode, not on every poll.
+local warned = false
+
+function M.on_load()
+    bread.on("bread.power.battery.low", function(event)
+        if warned then return end
+        warned = true
+        local pct = event.data.battery_percent or "?"
+        bread.notify("Battery low (" .. pct .. "%). Plug in soon.", {
+            urgency = "critical",
+            title   = "Battery",
+            timeout = 10000,
+        })
+    end)
+
+    -- Reset once back on AC so the next low episode warns again.
+    bread.on("bread.power.ac.connected", function()
+        warned = false
+    end)
+end
+
+return M