Tray: Phosphor icons, click-to-copy fields with feedback, steady plot column

- Bundle egui-phosphor (pinned to egui 0.31) and register its glyphs, so the
  icon buttons render real icons instead of tofu: refresh, shuffle (generate
  secret), pencil/check/x (rename host), copy (Copy secret).
- Copying is now the field itself, not a separate button: clicking the
  shortened device id, the network name, the network id, a range or an address
  copies the full value and the field flashes green "Copied" for a second
  (tracked in egui temp memory, so it clears itself). The standalone copy
  buttons are gone.
- In the devices window the connected-peers "rate / plot" column put the rate
  and the inline sparkline in a shared row, so the plot shifted as the rate
  text changed width ("0 B/s" vs "1.1 kB/s"). The rate now sits in a
  fixed-width, truncating cell, so the plot stays put.

Builds and is clippy-clean (-D warnings) on macOS; the UI has not been run in
this headless session.

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

Cargo.lock

@@ -187,7 +187,7 @@ dependencies = [
  "objc2-foundation 0.3.2",
  "parking_lot",
  "percent-encoding",
- "windows-sys 0.52.0",
+ "windows-sys 0.60.2",
  "x11rb",
 ]
 
@@ -1454,6 +1454,15 @@ dependencies = [
  "profiling",
 ]
 
+[[package]]
+name = "egui-phosphor"
+version = "0.9.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "171d57331491e92f0a7c73fad1088716e3200984309f4f8684731b750cee1378"
+dependencies = [
+ "egui",
+]
+
 [[package]]
 name = "egui-wgpu"
 version = "0.31.1"
@@ -5046,7 +5055,7 @@ dependencies = [
  "errno",
  "libc",
  "linux-raw-sys 0.4.15",
- "windows-sys 0.52.0",
+ "windows-sys 0.59.0",
 ]
 
 [[package]]
@@ -6319,6 +6328,7 @@ name = "tsunagi-tray"
 version = "0.1.0"
 dependencies = [
  "eframe",
+ "egui-phosphor",
  "tokio",
  "tracing",
  "tracing-subscriber",