feat: expand component library with bar chart, content cards, and layout helpers

Add BarChart component that renders multi-row Unicode bar charts with
anchored Y-axis labels, automatic tick-step computation, sub-sampling
for narrow terminals, and optional X-axis date labels. The chart
gracefully degrades to a sparkline when width/height is too small.

Add ContentCard, CardRow, and CardInnerWidth utilities for consistent
bordered card layout across all dashboard tabs. ContentCard renders
a lipgloss-bordered card with optional bold title; CardRow joins
pre-rendered cards horizontally; CardInnerWidth computes the usable
text width after accounting for border and padding.

Add LayoutRow helper that distributes a total width into n integer
widths that sum exactly, absorbing the integer-division remainder
into the first items -- eliminates off-by-one pixel drift in multi-
column layouts.

Refactor MetricCard to accept an outerWidth parameter and derive the
content width internally by subtracting border, replacing the old
raw-width parameter that required callers to do the subtraction.
MetricCardRow now uses LayoutRow for exact width distribution.

Refine TabBar to render all tabs on a single row when they fit within
the terminal width, falling back to the two-row layout only when
they overflow.

Simplify StatusBar by removing the unused filterInfo append that was
cluttering the left section.

internal/tui/components/statusbar.go

@@ -9,23 +9,19 @@ import (
 )
 
 // RenderStatusBar renders the bottom status bar.
-func RenderStatusBar(width int, filterInfo string, dataAge string) string {
+func RenderStatusBar(width int, dataAge string) string {
 	t := theme.Active
 
 	style := lipgloss.NewStyle().
 		Foreground(t.TextMuted).
 		Width(width)
 
-	left := " [f]ilter  [?]help  [q]uit"
+	left := " [?]help  [q]uit"
 	right := ""
 	if dataAge != "" {
 		right = fmt.Sprintf("Data: %s ", dataAge)
 	}
 
-	if filterInfo != "" {
-		left += "  " + filterInfo
-	}
-
 	// Pad middle
 	padding := width - lipgloss.Width(left) - lipgloss.Width(right)
 	if padding < 0 {