ci(docs): smoke start, troubleshoot, reference, and integration journeys

[CompleteDotTech]

Summary

Completes the browser-smoke coverage required by issue #778 for the four
canonical journey routes: start, troubleshoot, reference, and
integration.

• The coven-docs pull-request CI lane itself already exists: docs.yml runs on
  every pull_request and executes pnpm verify (build + content/link/anchor
  validation + browser smoke). It landed in refactor: certify and redesign the Coven documentation release surface OpenCoven/coven-docs#56, after #778 was filed — this PR
  does not duplicate it.
• The existing smoke, however, covered no integration route at all. This
  change tags the existing start/reference/troubleshoot journey stops and adds
  the missing integration stops: /docs/harnesses and /docs/harnesses/codex
  (the Harnesses section is Coven's integration surface: built-in harness
  adapters — codex, claude, coven-code, copilot).
• scripts/smoke-docs.mjs now hard-fails if any required journey loses its
  routes, and records the journey → route map in output/docs-smoke/report.json
  as CI evidence (uploaded by docs.yml as docs-certification-* artifacts).

Slice note: this is the remaining slice of #778's "browser smoke for start,
troubleshoot, reference, and integration routes"; the PR CI (build + link
validation) part of #778 was already delivered by OpenCoven#56 and is unchanged here.

Source of truth

• ci(docs): add canonical docs build, link, and browser journey OpenCoven/coven#778 and umbrella docs: progressive disclosure, single-source docs, and E2E certification OpenCoven/coven#670 ("coven-docs PR CI
  builds, validates links, and browser-tests the primary journey").
• Expected text verified against the owning content:
  content/docs/harnesses/index.mdx ("Built-in harnesses") and
  content/docs/harnesses/codex.mdx ("Coven launches it as a project-rooted
  PTY").
• Section stability from docs/site-manifest.json (harnesses: stable, owner
  OpenCoven/coven), rendered through components/docs-status.tsx.

Issue

Refs OpenCoven/coven#778
Closes OpenCoven/coven#778

Stability impact

• No product-contract change

Public surface

• No public-surface change

CI smoke coverage only; no routes, redirects, navigation, or visuals changed.

Test plan

• pnpm typecheck
• pnpm check (content, site-manifest, link, anchor, automation checks +
  23 api-runner tests) — all green
• pnpm build:site from the working tree — build green (86 doc paths)
• SSR assertion pass against the built site for all five journey routes:
  HTTP 200, expected text, exactly one h1/main, canonical link,
  data-docs-stability="stable", contract-source link
• git diff --check
• Full browser smoke pnpm verify (Chromium leg) — deferred to CI; this
  sandbox cannot run Chromium (no system X/Glib libraries, no root)

Vehicle note: opened in the fork CompleteDotTech/coven-docs as the CI
vehicle — this token cannot write to OpenCoven/coven-docs. Re-target upstream
once write access is restored. Refs OpenCoven/coven#778.

[CompleteDotTech]

CI verdict — unrelated, pre-existing failure; PR stays draft (no fake green)

The Verify documentation release job fails at "Verify upstream source freshness" (pnpm check:source-drift, run 33320605855) — a step that runs before anything from this branch is exercised. This branch touches only scripts/smoke-docs.mjs (+43/−2); it does not modify the source lock or any watched path.

The failure exists on current main too: docs/source-lock.json pins OpenCoven/coven at 9527145 (verified 2026-08-25), and 3 watched paths on upstream main moved since:

• crates/coven-cli/src/main.rs — 3dd51ed feat(codex): relay per-turn token usage through the stream-json result (#853); 4aa5b35 feat(doctor): report shadowed coven installs (#849); 882fc83 feat(automations): routine definitions and control actions (#846)
• crates/coven-cli/src/api.rs — bd3b47d feat(automations): daemon tick thread; 882fc83 feat(automations): routine definitions (part 1)
• crates/coven-cli/src/setup/process.rs — c291b72 fix(setup): extract versions that end in a sentence period (#850)

Re-pinning the lock means re-verifying those contracts (and, for the automations work, their canonical pages). That reconciliation is already in flight in OpenCoven#77 for issue OpenCoven#75 ("docs-stale: upstream contract sources changed"), so this PR deliberately does not duplicate it.

Meanwhile this branch's own behavior was validated locally: pnpm typecheck, pnpm check (content/link/anchor/automation + 23 api-runner tests), pnpm build:site, and an SSR assertion pass over the built site for all five journey routes (/docs/guide/getting-started = start, /docs/reference/api = reference, /docs/reference/troubleshooting = troubleshoot, /docs/harnesses + /docs/harnesses/codex = integration): HTTP 200, expected text, exactly one h1/main, canonical link, data-docs-stability="stable", contract-source link. The Chromium leg itself (pnpm verify) runs here in CI and could not run in the authoring sandbox (no system X/GLib libraries, no root).

Once the OpenCoven#77 reconciliation lands, re-running this PR's checks should let the full verify — including the new journey smoke — execute end to end.