v1.1.4 — Unused code removal

• Remove translation keys that no screen reads (guide.category.all, guide.choose and guide.why), the binWidth field of histogram results that no caller reads, and the feedback form placeholder check, which was always true because the form URL is set. The pages do not change (#40).
• Align the README, the specification and the comments with the code, and add comments on the reasons behind focus handling, URL state, tick limits and gamma sampling (#40).
• Validate lint, type checking, 62 tests and production build on Node.js 24; the published site serves the new bundle without the removed keys, renders the charts without console errors and still shows the feedback form link.