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, 1 insertions, 1 deletions

diff --git a/internal/collector/types.go b/internal/collector/types.go
index b0db600..13bcb1f 100644
--- a/internal/collector/types.go
+++ b/internal/collector/types.go
@@ -7,7 +7,7 @@ type CPULine struct {
 }
 
 // Total returns sum of all CPU counters.
-func (c *CPULine) Total() int64 {
+func (c CPULine) Total() int64 {
 	return c.User + c.Nice + c.System + c.Idle + c.Iowait + c.IRQ + c.SoftIRQ + c.Steal + c.Guest + c.GuestNice
 }