feat: triple-toggle CPU display mode via 1 key; add tooltip, font, hit-test

CPU display now cycles through three states with each press of 1:
  0 = CPUModeAverage  – aggregate bar only (default)
  1 = CPUModeCores    – individual core bars + aggregate
  2 = CPUModeOff      – all CPU bars hidden

Config file stores cpumode=N (integer); old showcores=0/1 is read for
backward compatibility. CLI flag --showcores replaced by --cpumode.

Other improvements landed in this commit:
- internal/display: add font.go (text rendering), hittest.go (bar hit
  testing), tooltip.go (mouse-over tooltip), tooltip_test.go
- internal/display: mouse tracking and drawOverlay hook in display.go
- internal/display: update build tags to //go:build form
- internal/collector: embed remote script via script_embed.go /
  scriptdata/loadbars-remote.sh
- internal/collector: CPULine.Total() changed to value receiver
- internal/collector: table test improvements (name field, t.Run)
- internal/constants: BytesPerSec consts promoted from var to const
- Magefile.go: fix error formatting and install path

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

1 files changed, 18 insertions, 16 deletions

diff --git a/internal/collector/parse_test.go b/internal/collector/parse_test.go
index ec77067..fe7a73c 100644
--- a/internal/collector/parse_test.go
+++ b/internal/collector/parse_test.go
@@ -44,29 +44,31 @@ func TestParseCPULine(t *testing.T) {
 
 func TestParseMemLine(t *testing.T) {
 	tests := []struct {
+		name      string
 		line      string
 		wantKey   string
 		wantValue int64
 		wantOK    bool
 	}{
-		{"MemTotal:       123456 kB", "MemTotal", 123456, true},
-		{"MemFree:         99999 kB", "MemFree", 99999, true},
-		{"Buffers:             0 kB", "Buffers", 0, true},
-		{"not a mem line", "", 0, false},
-		{"", "", 0, false},
+		{"MemTotal", "MemTotal:       123456 kB", "MemTotal", 123456, true},
+		{"MemFree", "MemFree:         99999 kB", "MemFree", 99999, true},
+		{"Buffers_zero", "Buffers:             0 kB", "Buffers", 0, true},
+		{"not_a_mem_line", "not a mem line", "", 0, false},
+		{"empty_string", "", "", 0, false},
 	}
 	for _, tt := range tests {
-		got, ok := ParseMemLine(tt.line)
-		if ok != tt.wantOK {
-			t.Errorf("ParseMemLine(%q) ok = %v, want %v", tt.line, ok, tt.wantOK)
-			continue
-		}
-		if !tt.wantOK {
-			continue
-		}
-		if got.Key != tt.wantKey || got.Value != tt.wantValue {
-			t.Errorf("ParseMemLine(%q) = %+v, want key=%q value=%d", tt.line, got, tt.wantKey, tt.wantValue)
-		}
+		t.Run(tt.name, func(t *testing.T) {
+			got, ok := ParseMemLine(tt.line)
+			if ok != tt.wantOK {
+				t.Fatalf("ParseMemLine(%q) ok = %v, want %v", tt.line, ok, tt.wantOK)
+			}
+			if !tt.wantOK {
+				return
+			}
+			if got.Key != tt.wantKey || got.Value != tt.wantValue {
+				t.Errorf("ParseMemLine(%q) = %+v, want key=%q value=%d", tt.line, got, tt.wantKey, tt.wantValue)
+			}
+		})
 	}
 }