Add funnel telemetry for documentation journeys

[David Pine (IEvangelist)]

Summary

• add a versioned, consent-gated funnel event contract for CLI installation, getting started, search, integrations, deployment, troubleshooting, 404 recovery, and existing-app adoption
• instrument shared components plus relevant English and Japanese guides with bounded stage and dimension metadata
• correlate short-lived same-origin continuation outcomes
• prevent raw search queries, query-bearing URLs, raw referrer paths, and arbitrary 404 paths from entering analytics payloads
• keep the CLI installation funnel limited to reliable browser-side stages through command_copied; server-side request measurement remains deferred until StaticHost has a compatible telemetry exporter

This replaces #1583 because its deleted fork head could not be reopened or retargeted. This branch is hosted directly in microsoft/aspire.dev and is rebased onto the latest main.

Fixes #1582

OneDS auto-capture decisions

• pageView: false and onLoad: false remain intentional: those events are captured manually after URL sanitization is registered, avoiding duplicate initial events and adding one deduplicated page view per Astro route.
• jsError: true preserves automatic JavaScript error collection.
• existing onUnload, click, scroll, and resize collection remains enabled.
• SPA page views now receive an explicit canonical previous-route referrer; external referrers are reduced to origin only.

Third-party links and affiliations

None.

Validation

• targeted ESLint for changed analytics scripts and tests
• pnpm --dir ./src/frontend exec vitest run --config vitest.config.ts tests/unit/analytics-script-contracts.vitest.test.ts tests/unit/custom-components.vitest.test.ts (75 passed)
• pnpm --dir ./src/frontend exec playwright test tests/e2e/analytics-scripts.spec.ts (60 passed across desktop, tablet, and mobile Chromium)
• pnpm --dir ./src/frontend run build:skip-search (15,210 pages built; internal links valid)
• local Chromium hot-path benchmark: unrelated clicks measured 4.13 µs each versus 3.27 µs on main (+0.86 µs); analytics scripts add about 6.2 KB Brotli-compressed combined

[aspire-repo-bot]

Frontend HTML artifact ready

The latest frontend build uploaded the frontend-dist artifact for PR #1652. Use the VS Code button below to open this PR with GitHub Artifacts Explorer and browse the built HTML locally.

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