Improve result plots for the paper

[byeongjee]

Summary

• Normalized plots drop the reference series (Uninstrumented / BAO) and name it in a two-line y-axis title ("Relative Execution Time" / "(to BAO)").
• Bar value labels are vertical, at a fixed gap above their own bar, with headroom derived from the longest label; the cluster/tier placement heuristic is gone. Normalized values are shortened (11.5, 1401).
• Series order is BAO, ROCKCLIMB, SCHEMATIC, SCHEMATIC-O3, Uninstrumented everywhere.
• Fill patterns are distinct types (diagonal stripes, crosshatch, dots, horizontal stripes, solid) with absolute spacing, so bars, boxes, and legend keys look the same across plots and stay distinguishable in greyscale.
• plot_intermittent.R takes labels/colours/patterns from plot_config.json and uses the same y-title; shared helpers moved to scripts/plot_common.R.
• Removed the matplotlib ckpt analyze plot command and the non-normalized region-boundary PDFs; regenerated the committed plots.

Test plan

• Rscript scripts/plot_results.R --result-dir results --output-dir results/plots (default, --absolute --all-metrics, --log-scale, and --config scripts/plot_config_o0.json) render without errors
• Rscript scripts/plot_intermittent.R --result-dir results/intermittent
• uv run ruff check, pyright, and uv run pytest tests/test_capacitor_support.py