docs: sync shortcut.luau in plan with review fixes

docs/superpowers/plans/2026-08-31-headsetcontrol-plugin.md

@@ -1025,6 +1025,8 @@ local hsc = require("./lib/hsc.luau")
 
 local on = false
 local battery = nil
+local capsSidetone = false
+local errorState = ""
 
 local function render()
   local label = on and noctalia.tr("shortcut.on") or noctalia.tr("shortcut.off")
@@ -1039,7 +1041,7 @@ end
 local function currentSidetone()
   local v = noctalia.state.get("sidetone")
   if v ~= nil then return v end
-  return noctalia.getConfig("sidetone_default")
+  return noctalia.getConfig("sidetone_default") or 64
 end
 
 local function apply(value)
@@ -1055,6 +1057,7 @@ local function apply(value)
 end
 
 function onClick()
+  if not capsSidetone or errorState ~= "" then return end
   if on then
     apply(0)
   else
@@ -1062,12 +1065,45 @@ function onClick()
   end
 end
 
-noctalia.state.watch("battery", function(v) battery = v; render() end)
+local function syncState()
+  local v = noctalia.state.get("caps")
+  if v then capsSidetone = v.sidetone == true end
+  v = noctalia.state.get("error")
+  if v ~= nil then errorState = v end
+  v = noctalia.state.get("sidetone")
+  if v ~= nil then
+    on = v > 0
+  end
+end
+
+function onCapsChanged(v)
+  capsSidetone = v ~= nil and v.sidetone == true or false
+end
+
+function onErrorChanged(v)
+  errorState = v or ""
+end
+
+function onSidetoneChanged(v)
+  if v ~= nil then
+    on = v > 0
+    render()
+  end
+end
+
+noctalia.state.watch("battery", function(v) battery = v or battery; render() end)
+noctalia.state.watch("caps", onCapsChanged)
+noctalia.state.watch("error", onErrorChanged)
+noctalia.state.watch("sidetone", onSidetoneChanged)
+
 local b = noctalia.state.get("battery")
 if b then battery = b end
+syncState()
 render()
 ```
 
+> Review notes: `on` syncs with the shared `sidetone` state on load and via a watcher, so entry hot-reloads no longer invert the toggle and panel changes propagate. `onClick` is gated on `caps.sidetone` and a clean `error` state. `capsSidetone`/`errorState` must be declared BEFORE `onClick` (a forward reference to a `local` inside a function body resolves to a global nil in Lua/Luau and would disable the gate).
+
 - [ ] **Step 2: Verify the shortcut renders (hot-reload)**
 
 Open the control center. The tile labeled "Sidetone off" (or "Sidetone on" after enabling) with a music icon should be present. Clicking toggles sidetone (mock mode: toggles state without touching hardware).