Add icon commands and more fonts; clean the workspace and disable bot PRs

[YaoxiangLi]

The editor's text-heavy command rows and three generic font choices made common figure edits hard to scan. This update replaces editing actions with consistent SVG icons and hover/keyboard tooltips, expands the figure font catalog to seven portable families, and removes the old workspace styles and unused code.

• Add icon controls for alignment/distribution, annotation actions, tools, file commands, layers, and text formatting, while retaining accessible names and keyboard behavior. Measure each font's actual editing baseline so labels stay aligned during direct editing.
• Add Carlito, Lato, Source Sans 3, and Source Serif 4 in four faces each, with pinned sources, SHA-256 checksums, and upstream OFL notices. Clearly label Arial/Helvetica-style and other familiar-name alternatives and embed the same files in vector exports. Preserve the original default font and 6.8-inch figure.
• Remove Dependabot configuration as requested. PRs Bump the github-actions group across 1 directory with 8 updates #13, Bump the python-dependencies group across 1 directory with 2 updates #14, and Bump the web-dependencies group across 1 directory with 11 updates #16 were closed without merging, their branches deleted, and automatic security-update PRs disabled in repository settings. Keep CI dependency auditing.
• Remove obsolete layout rules, imports, an unused statistics wrapper, and approximately 3.6 GiB of ignored local build/download/debug artifacts. Enable TypeScript unused-code checks, document scoped cleanup, and refresh the user guide and screenshots.

Validation: 58 Python tests, 23 browser unit tests, all 30 Playwright scenarios in Chromium/Firefox/WebKit, 744 endpoint comparisons against Python/JavaScript/R with zero mismatches beyond tolerance, both fixture asset validators, Ruff, production build, dependency audit, and wheel/sdist checks. CSS cleanup was compared across 16 views before the intentional icon changes. The existing immutable data release is reused; deployment separately validates the full 51-cohort catalog and the 850 MiB Pages budget.