Drop the connection-state dot in favor of icon-tinted state

[buggerman]

Summary

• Follow-up to Add SF Symbol row icons to sidebar server, channel, and PM rows #32. With the antenna-in-circle icon now in front of the server name, the separate 8pt connection-state dot became redundant: two filled circles with the same role (signaling connection state) sat next to each other. Drop the dot and tint the icon itself with the state color so we have a single source of truth.
• Color mapping unchanged: green = connected/registered, yellow = connecting, orange = disconnecting. The previously-grey disconnected state is reinforced by the slash variant of the icon, so users with color-vision differences keep the redundant shape signal.

Changes

• Sources/Brygga/Views/ContentView.swift — ServerRow removes the Circle().fill(stateColor).frame(8x8) block. The existing Image(systemName: serverIconName) now applies .foregroundStyle(stateColor) instead of .secondary.

Test plan

• swift build — passes
• swift test — 131 tests pass (no test changes; UI-only)
• swiftformat --lint . — clean
• Manual:
  • Sidebar server row no longer shows two filled circles. Antenna icon takes on the state color (green / yellow / orange / grey-with-slash).
  • Connect / disconnect cycle: icon color follows the state, the slash variant only appears on stable .disconnected.
  • Light + dark mode both render correctly.

Risk / rollback

• Pure view-layer change. Revert: this single commit.