fix(site): complete LHTB brief publication

[huangruiteng]

Summary

• rebase and preserve @shangzh0's LHTB publication follow-up from feat(site): publish LHTB five-arm research brief #4707 on current main
• make the existing bilingual LHTB brief discoverable from the homepage and both README research indexes
• publish the route in the Frontstage bundle manifest and generated README
• validate the 46-task five-arm aggregate, bilingual labels, three-arm primary narrative, and real browser navigation
• keep strict-solve parity with Plain in the supporting result text instead of the section headline

Why a replacement PR

#4707 initially allowed maintainer edits, so its original contribution was rebased onto current main. The fork then disabled maintainer edits before the CI and copy repairs could be pushed. This branch preserves the rebased contributor commit and adds the focused maintainer repair required by the current mainline contract.

Validation

• uv run --extra test pytest benchmark/tests/test_publication_scope.py -q
• uv run --extra test node examples/frontstage-share-bundle-smoke.mjs
• node examples/dashboard-frontstage-design-baseline-smoke.mjs
• npm --prefix apps/presentation/site run build
• npm --prefix apps/presentation/dashboard run smoke:frontstage-browser
• desktop Chinese and mobile English LHTB checks in a real browser: 46 rows, bilingual titles, historical-arm toggle, and no document overflow

Supersedes #4707 while retaining @shangzh0's commit authorship and DCO sign-off.