Handle unitless QMCFC parameters

[galjos]

Summary

• normalize missing QMCFC units without inventing scientific units
• omit unavailable units from plot labels and show n/a in explicit TUI unit fields
• cover single plots, dashboards, terminal charts, and the TUI with a minimal QMCFC fixture

Verification

• reproduced with the issue attachment and parsed all 11,897 rows after the fix
• 200 unit and integration tests passed with 100% coverage
• 9 GUI and TUI end-to-end tests passed
• 210 total non-benchmark tests passed

Fixes #86