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/shortcut.luau

@@ -0,0 +1,33 @@
+--!nonstrict
+-- Mihomo Control — control-center shortcut.
+--
+-- Quick toggle for the proxy mode: clicking switches between rule and global.
+-- The tile shows the current mode and lights up while global mode is active.
+
+local function current_mode()
+  local config = noctalia.state.get("mihomo.config") or {}
+  return config.mode or "rule"
+end
+
+local function render()
+  local mode = current_mode()
+  shortcut.setLabel(noctalia.tr("shortcut.label", { mode = noctalia.tr("shortcut.mode_" .. mode) }))
+  shortcut.setIcon("cat")
+  shortcut.setActive(mode == "global")
+  shortcut.setEnabled(true)
+end
+
+noctalia.state.watch("mihomo.config", function(_value)
+  render()
+end)
+
+function onClick()
+  local next_mode = current_mode() == "global" and "rule" or "global"
+  noctalia.state.set("mihomo.command", {
+    op = "mode",
+    mode = next_mode,
+    seq = math.floor(os.clock() * 1000000),
+  })
+end
+
+render()