v2.4.12

Fixed — Update dialog: window much taller (and wider) than its content

The Check for Updates window reserved a fixed 420×180 client area regardless of what it
showed, so the common resting state ("You're on the latest version!" + the version line + an OK
button) floated in the top half with a large empty band underneath. Two coupled layout choices caused
it: the root panel was Dock.Fill inside a hard-pinned height (content stacked at the top, leftover
height became dead space), and the progress bar sat in an AutoSize row that collapsed when hidden —
so the height had been over-sized to stop the button jumping between states.

The dialog now sizes to its content, matching the same fix already shipped on the sibling apps' update
dialogs (MicMute / SyncthingPause):

• The root stack is Dock.Top + AutoSize; OnLoad pins the width to the DPI-scaled design width
  and fits the height to the realized content (FitToContentHeight), re-fitting on every state
  change so a long error/winget message that wraps to 2–3 lines still grows to fit (no clipped button).
• The progress bar moved into a reserved Absolute row, so the window is the same height whether
  the bar is shown (checking/downloading) or hidden (resting/error/winget) — the button no longer jumps
  and no dead band opens when the bar disappears.
• Design width tightened 420 → 360 to match the sibling family, trimming the excess side margins too.

Fixed — Update dialog: "Upgrade Now" button clipped to "Upgrade", thin progress bar at 150% DPI

While verifying the above at a real 150% scale (Tiny11 lab), a second defect surfaced: the action
buttons used hardcoded pixel sizes (110×30 / 80×30) and the progress track a hardcoded 312×18.
AutoScaleMode.Dpi does not scale a fixed control Size in this dialog (only point-fonts grow with
DPI), so at 150% the larger font outgrew the fixed-width button and "Upgrade Now" clipped to
"Upgrade", while the progress bar stayed 96-DPI-narrow.

• Buttons are now AutoSize (with padding), so they grow to fit the scaled text at any DPI and can
  never clip — the same pattern as SettingsForm's buttons (the app's DPI convention: layout-driven
  sizing, not absolute pixels relying on a scale pass).
• The progress track is now scaled explicitly via LogicalToDeviceUnits in OnLoad (the reserved row
  height kept in sync), so it stays proportional — 312×18 at 100%, 468×27 at 150%.

Verified by ground-truth on-screen capture (CopyFromScreen + a content-bottom pixel scan, not
DrawToBitmap, which mis-composites this UserPaint form) at a real 100% and a real 150% scale on
the Tiny11 lab: client 360×136 / 540×171, the button row sits inside the client with a 12px gutter
at both scales, and "Upgrade Now" renders in full.

Full Changelog: v2.4.11...v2.4.12