log-ui 0.3.0

Added

• Key plots replace pinned charts: charts at the top of the workspace and run page that overlay several metrics
  on one y axis (e.g. train/loss with val/loss). A metric can be in any number of key plots (A+B, A+C,
  A+D at once). Add metrics from any chart's pin menu or a plot's + picker; rename plots; remove metrics
  or whole plots. Existing pins become single-metric key plots automatically.
• Line styles for overlaid metrics while colour stays the run: 6 dash patterns, 4 sparse marker shapes and
  3 thicknesses, assigned automatically (30 distinct before repeating) and changeable per metric from the
  plot's legend.

Changed

• Tooltips show every line's nearest logged value, marked with its step when not exactly under the cursor,
  so metrics logged at different steps (or downsampled to different points) all appear. Steps in tooltips
  are exact (step 1,026) instead of rounded.
• A metric in a key plot stays in its group below (pinned charts used to move out of their group).