Redesign the Election Trends chart, restyle election tables, add a catalogue section bar

[ACoci86]

Summary

Redesigns the Election Trends chart as a newsroom-style line chart, restyles the election pane tables to match, gives the maps catalogue a pinned section bar with Lucide icons, fixes the Books section layout, and lines the About page up with Home.

Everything the change touches, with the reasoning, is written up in docs/election-trends-chart-and-catalogue-ui.md.

What changed

Election Trends chart (src/election-trend-chart.mjs, new; app/src/election-manager.js; app/src/test2.css)

• Real time axis with upright year labels, thin lines in the existing party colours, faint horizontal grid, percentage y-axis capped at 100.
• Direct labels at the end of each line with the latest share, shortening to abbreviation, value only, then hidden as the pane narrows; pushed apart with leader lines so they never collide.
• Real gaps: the line stops where a party has no comparable result, a faint dotted bridge crosses the missing elections, and a lone result is a dot. No value is drawn for an election a party did not contest.
• Crosshair and tooltip at the nearest election (mouse and touch), party focus by click, tap or key entry, arrow-key navigation, re-rendering at the container's real width.
• Same data path and comparable-election filter. Series ranking puts parties standing at the latest election first, then others by peak. loadTrendSummary falls back to the static bundle when _api is unavailable, as loadBundle already did.
• Existing test hooks kept; the Trends specs pass unchanged.

Election pane tables (app/src/test2.css, scoped to the pane)

• White surface, hairline row rules, no vertical grid, quiet bold headers, site font, only the share change coloured, one underlined link per row, a dot for Elected. The shared table rules in assets/css/main.css are untouched.

Timeline buttons (app/src/app.js)

• Play and stop only animate boundary layers and were always disabled while an election was open; they now hide instead.

Maps catalogue (src/ui-controller.js, assets/css/main.css, maps/index.html)

• Elections, Maps, Books and Tables in a segmented bar above the contents box, pinned under the search shell, with Lucide icons. Links keep their classes and data attributes, so click handling is unchanged. The active tab survives re-renders.
• Icons on the Elections and Maps headings inside the box, a rule and gap between sections, a Tables heading in the Tables pane.
• Books: Lucide icons by category instead of the emoji from books.json; the category heading spans the grid (the first card used to jump to the right column); the cover fallback badge hides once a cover loads (both used to draw on top of each other); cards are compact rows with the transcription notice in the Markdown button's tooltip.

About page (pages/about.html, assets/pages/css/about.css)

• Same wide wrapper as Home, prose no longer capped at 68 characters, stylesheet linked with a content-hash ?v=.

Build output (app/build/*, sw.js, cache tokens in maps/index.html) rebuilt with the project's scripts.

Verification

• npm run build: exit 0, performance dashboard 9/9.
• Playwright: the Trends, election, catalogue, Tables and Books specs in app.spec.js and election-layout.spec.js, 21 passed.
• npm run lint: 60 warnings before and after, none new.
• check:app-shell-cache, check:site-figures, check:pages-assets, check:root, check:site-partials, check:site-nav, check:asset-refs: pass. check:doc-paths fails on UX-REMEDIATION-PLAN.md on main too, unrelated.
• Checked in a browser at 1920, 1600, 1280, 1000, 700 and 390 px, light and dark, with touch emulation.

Notes

• Not changed: the election data pipeline, map, URL and hash state, selectors, overlays, party colours, Browse.
• Left alone, pre-existing: clicking Maps in the section bar lands part-way into the section rather than on its heading; the Dáil candidate table is wider than the pane and scrolls sideways with the name columns pinned.