[ggkouujere-debug]

What

Redraws the progress history chart (tools/progress_history.py) as proposed in #6997:

• One panel per measure (system library functions, GPU shader instructions) sharing the date axis, each with its own y-scale — the two unrelated measures no longer share one axis and the shader line is no longer flattened.
• Same encoding in both panels: implemented as a solid line with fill, declared as a dashed line; the current percentage sits beside each panel's labels. Labels now say what they count ("System library functions", "GPU shader instructions").
• The shader panel draws the declared total from tools/rdna_isa.txt (the same total the progress page uses) — previously only the implemented count was drawn, hiding that shaders are at 1166/1166.
• Horizontal date labels that thin out as history grows (no more 60° rotation); every day gets a hover tooltip via an invisible rect (previously tooltips existed only for series up to 45 points).
• Incorporates fix(progress_history): label axis dates on calendar days #6574's calendar-day label fix (labels walk every calendar day, not just days with commits) so the rewrite does not regress it; fix(progress_history): label axis dates on calendar days #6574's test is included.

Tested

• New test_chart_shows_a_declared_total_per_panel: two panels, one dashed declared line per panel, percentage labels.
• Updated test_long_series_keeps_the_chart_readable: no rotated labels; dots only for short series; one hover tooltip per day at every length.
• test_axis_labels_fall_on_calendar_days_without_commits (from fix(progress_history): label axis dates on calendar days #6574) passes.
• Rendered SVG validated as well-formed XML; geometry sanity-checked (independent panel scales, right-label de-collision at ~100%).
• Full tools/tests suite: 559 tests pass (22 pre-existing platform skips).
• python3 tools/check_conventions.py --base origin/main: pass.

Checklist

• Based on current main; no other open PR implements the same functions
• One topic per PR; follow-ups go in a new PR
• No comments in code except technical debt
• Unimplemented paths throw (NotImplemented_nid_no_patch); silent stubs are listed under Silent stubs in their library's technical debt file
• No notes, investigation .md files or images added to the repository (attach them to this PR)
• New third-party code is a submodule built from source
• Generic behaviour, not specific to one title
• Depends on: none
• Fixes: tools: progress history chart has no shader instruction total #6997
• Unblocks: none
• GPUs tested: n/a
• AI-assisted: yes

[github-actions]

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