fix(lazy-loader): bump default rootMargin to 2000px so dedicated dashboard pages load without user scroll

[Copilot]

Plan

Live regression: on dedicated /dashboards/<name>.html pages the single dashboard container sits ~1 156 px below the fold of a 720 px viewport. With the previous rootMargin: '200px', the IntersectionObserver in lazy-loader.ts never fired without user scroll → Chart.js / D3 / PapaParse were never registered → all charts rendered empty and dashboards' init() failed with misleading error fallbacks ("Cannot access 'o' before initialization", "Unable to load risk assessment data from CIA Platform"). The per-chart Cypress suite did not catch this because cy.visitDashboard() unconditionally scrollIntoView()s the container.

Fix

• src/browser/lazy-loader.ts
  • New exported DEFAULT_ROOT_MARGIN = '2000px' (≈ 2 viewport heights — covers the ~1 156 px below-fold offset on every dedicated dashboard page) and DEFAULT_THRESHOLD = 0.01 constants.
  • initLazyDashboards() now defaults to these.
  • Belt-and-suspenders eager-load fallback: one requestAnimationFrame after registration, the loader probes each container's getBoundingClientRect() against the configured rootMargin and synthesises a load for anything that would intersect — fires the loader exactly once even in browser/iframe contexts that don't deliver an initial IO entry without user-driven scroll.
  • New exported parseRootMarginPx() helper.
• tests/lazy-loader.test.js
  • Lock the DEFAULT_ROOT_MARGIN = "2000px" / DEFAULT_THRESHOLD = 0.01 regression contract.
  • Assert initLazyDashboards() passes those values to the IntersectionObserver by default.
  • 7 new parseRootMarginPx() unit tests covering px / negative / percentage / undefined / empty / malformed inputs.
  • 30 / 30 passing (npx vitest run tests/lazy-loader.test.js).
• cypress/e2e/dashboards-no-scroll.cy.js (new spec — would have caught the live regression)
  • Visits all 9 dedicated dashboard pages (parties, committees, coalitions, election-cycle, seasonal-patterns, pre-election, anomaly-detection, ministers, risk).
  • Does NOT scroll — asserts what a user actually sees on first paint.
  • Per page: hashed main-*.js bundle is served (no /src/browser/main.ts dev path); window.Chart + window.d3 register within 15 s without any scroll; no visible .error-message / [role="alert"] containing user-facing error text is rendered (skips empty placeholder banners like risk.html's #earlyWarnings).
  • 27 / 27 passing locally against vite preview (npx cypress run --spec cypress/e2e/dashboards-no-scroll.cy.js).
• npx tsc --noEmit -p tsconfig.browser.json → clean.

Geometry that proves the fix

viewport: 0…720 px
container (#committee-dashboard / #risk-dashboard / …): top=1156, bottom=2916
old effective root (200 px margin):   −200 …  920  → no intersection → no load → broken charts
new effective root (2000 px margin):  −2000… 2720  → intersects     → eager load → charts render

[Copilot]

Copilot wasn't able to review this pull request because it exceeds the maximum number of files (300). Try reducing the number of changed files and requesting a review from Copilot again.

[github-actions]

🔍 Lighthouse Performance Audit

Category	Score	Status
Performance	85/100	🟡
Accessibility	95/100	🟢
Best Practices	90/100	🟢
SEO	95/100	🟢

📥 Download full Lighthouse report

Budget Compliance: Performance budgets enforced via budget.json

[github-actions]

🏷️ Automatic Labeling Summary

This PR has been automatically labeled based on the files changed and PR metadata.

Applied Labels: documentation,html-css,javascript,translation,rtl,testing,size-xl,news

Label Categories

• 🗳️ Content: news, dashboard, visualization, intelligence
• 💻 Technology: html-css, javascript, workflow, security
• 📊 Data: cia-data, riksdag-data, data-pipeline, schema
• 🌍 I18n: i18n, translation, rtl
• 🔒 ISMS: isms, iso-27001, nist-csf, cis-controls
• 🏗️ Infrastructure: ci-cd, deployment, performance, monitoring
• 🔄 Quality: testing, accessibility, documentation, refactor
• 🤖 AI: agent, skill, agentic-workflow

For more information, see .github/labeler.yml.

[github-actions]

🔍 Lighthouse Performance Audit

Category	Score	Status
Performance	85/100	🟡
Accessibility	95/100	🟢
Best Practices	90/100	🟢
SEO	95/100	🟢

📥 Download full Lighthouse report

Budget Compliance: Performance budgets enforced via budget.json

[Copilot]

Copilot wasn't able to review this pull request because it exceeds the maximum number of files (300). Try reducing the number of changed files and requesting a review from Copilot again.