fix(viewer): improve topology and sysinfo layout on narrow screens

[thinkingfish]

Summary

• Remove compact mode from CPU topology, always use labeled mode with responsive column wrapping
• Group sub-groups by core type (P-core vs E-core) for balanced row packing on hybrid Intel CPUs — prevents uneven rows like 5+3 instead of 4+4
• Fix sysinfo card overflow on narrow screens (min-width, word-break, overflow containment)
• Remove dead compact-mode CSS (~50 lines) and legend rendering code (~100 lines)

Test plan

• Load cachecannon.parquet in viewer, resize to narrow widths — verify topology rows are balanced
• Check hybrid CPU topology (P+E cores) renders with even rows per core type
• Verify sysinfo cards don't overflow on narrow screens
• Confirm cache toggle and NUMA toggle still work correctly

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