Dev/mihomo control (#339)

* Add Mihomo Control plugin

Monitor and control a Mihomo (Clash Meta) external controller from the
bar: live traffic graph, proxy mode, proxy-group management with latency
tests, and core restart. Works locally (127.0.0.1) or remotely via
host/port/secret settings.

* Add Chinese (Simplified) translation

* Add test-all latency button

Adds a Test all button next to the Proxy groups heading that runs latency
tests on every group sequentially, with a single summary notification.

* Unify traffic and proxy groups section styles

Give both sections the same card look: muted medium-weight heading on the
left, secondary info on the right, and proxy-group cards restyled as
bordered sub-cards inside the section.

* Polish proxy group cards

Show the selected proxy next to the bold group name (ECS > ecs-proxy),
move the expand chevron to the type/members row where the list opens,
and drop the list glyph from the card header.

* Decouple heights of paired group cards

Keep each card in a two-column row at its natural height instead of
stretching the neighbor when one is expanded.

* Use thumbnail generator to generate thumbnail

* mihomo-control: theme-aware panel colors

Use theme roles for traffic and latency colors so they stay readable in
light mode, and keep the status chip's green/amber/red identity with
darker light-mode shades.

mihomo-control/widget.luau

@@ -0,0 +1,100 @@
+--!nonstrict
+-- Mihomo Control — bar widget.
+--
+-- Shows live download/upload rates from the service's streamed /traffic data.
+-- Left click toggles the control panel; the tooltip holds the connection
+-- status, mode, totals, connection count and the current selection of every
+-- proxy group.
+
+local PLUGIN_ID = "mdj2812/mihomo-control"
+
+local function format_rate(bytes_per_second)
+  local value = tonumber(bytes_per_second) or 0
+  if value >= 1024 * 1024 * 1024 then
+    return string.format("%.2f GB/s", value / (1024 * 1024 * 1024))
+  end
+  if value >= 1024 * 1024 then
+    return string.format("%.1f MB/s", value / (1024 * 1024))
+  end
+  if value >= 1024 then
+    return string.format("%.1f KB/s", value / 1024)
+  end
+  return string.format("%d B/s", value)
+end
+
+local function render()
+  local conn = noctalia.state.get("mihomo.connection") or {}
+  local config = noctalia.state.get("mihomo.config") or {}
+  local traffic = noctalia.state.get("mihomo.traffic") or {}
+  local connections = noctalia.state.get("mihomo.connections") or {}
+  local groups = noctalia.state.get("mihomo.groups") or {}
+
+  local online = conn.status == "online"
+  local mode = noctalia.tr("panel.mode_" .. (config.mode or "rule"))
+  local icon_path = "icon-offline.png"
+  if online then
+    icon_path = "icon-online.png"
+  elseif conn.status == "connecting" then
+    icon_path = "icon-connecting.png"
+  end
+
+  local container = barWidget.isVertical() and ui.column or ui.row
+  barWidget.render(container({ gap = 6, align = "center" }, {
+    ui.image({ path = icon_path, width = 16, height = 16 }),
+    ui.label({ text = mode, fontSize = 12, color = "on_surface", fontWeight = "medium" }),
+  }))
+
+  local status_value = "Offline"
+  if online then
+    local version = tostring(conn.version or "")
+    status_value = version ~= ""
+      and noctalia.tr("widget.status_online_with_version", { version = version })
+      or noctalia.tr("widget.status_online_plain")
+  elseif conn.status == "connecting" then
+    status_value = noctalia.tr("widget.status_connecting")
+  elseif tostring(conn.error or "") ~= "" then
+    status_value = noctalia.tr("widget.status_offline_with_error", { error = conn.error })
+  else
+    status_value = noctalia.tr("widget.status_offline_plain")
+  end
+
+  local tooltip = {
+    { key = noctalia.tr("widget.status"), value = status_value },
+    { key = noctalia.tr("widget.mode"), value = noctalia.tr("panel.mode_" .. (config.mode or "rule")) },
+    { key = noctalia.tr("widget.down"), value = `▼ {format_rate(traffic.down)}` },
+    { key = noctalia.tr("widget.up"), value = `▲ {format_rate(traffic.up)}` },
+    { key = noctalia.tr("widget.connections"), value = tostring(connections.count or 0) },
+  }
+  for _, group in ipairs(type(groups) == "table" and groups or {}) do
+    if #tooltip < 14 then
+      table.insert(tooltip, {
+        key = tostring(group.name or ""),
+        value = tostring(group.now or "—"),
+      })
+    end
+  end
+  barWidget.setTooltip(tooltip)
+end
+
+for _, key in {
+  "mihomo.connection",
+  "mihomo.config",
+  "mihomo.traffic",
+  "mihomo.connections",
+  "mihomo.groups",
+} do
+  noctalia.state.watch(key, function(_value)
+    render()
+  end)
+end
+
+function update()
+  noctalia.setUpdateInterval(1000)
+  render()
+end
+
+function onClick()
+  noctalia.togglePanel(PLUGIN_ID .. ":panel")
+end
+
+render()