fix: window minimum, stock spacing layout, sidebar width floor

Part A stages 1-3 of the GUI layout cleanup plan:

- Stage 1 (F1-F3): delete settingsControlWidth's redundant wrapper (the
  Border centre slot already stretches controls), truncate the config
  path label, and name the default window size so it can be asserted
  against. Settings no longer widens the window past what it asks for.
- Stage 2 (F4-F5): drop compactVBoxLayout for the stock
  layout.NewCustomPaddedVBoxLayout and a single derived rowOverlap()
  spacing, replacing three hand-tuned spacing constants.
- Stage 3 (F7): delete the inert 400px sidebar width floor; the Border
  left slot already renders it at content MinSize.

See docs/PLAN-gui-layout.md.

src/ui/jobs_view_details.go

@@ -6,6 +6,7 @@ import (
 
 	"fyne.io/fyne/v2"
 	"fyne.io/fyne/v2/container"
+	"fyne.io/fyne/v2/layout"
 	"fyne.io/fyne/v2/theme"
 	"fyne.io/fyne/v2/widget"
 )
@@ -121,7 +122,7 @@ func (d *detailsPanel) container() fyne.CanvasObject {
 	// keeping the details pane usable on 720p screens where a single column of
 	// ten rows pushes the minimum window height past the available space.
 	capW := detailCaptionWidth()
-	rows := container.New(compactVBoxLayout{spacing: detailRowSpacing},
+	rows := container.New(layout.NewCustomPaddedVBoxLayout(rowOverlap()),
 		detailRowPair(capW, "Folder", d.folder, "Schedule", d.schedule),
 		detailRowPair(capW, "Command", d.command, "Arguments", d.arguments),
 		detailRowPair(capW, "Run mode", d.runMode, "Overlap policy", d.overlapPolicy),