Refocus Home on the particle stage

[130U]

Summary

• make the particle wordmark the sole visual focus of the opening viewport
• remove the Home-only profile sidebar and the former “Quis ego sum?” / thesis copy
• move Theodore Ouyang’s identity, credentials, biography, and contact coordinates into a restrained editorial section below the fold
• keep the particle system bounded to the opening viewport and retain its existing fallback and reduced-motion behavior
• isolate all new layout rules in a Home CSS module

Protected scope

Education, Past Experience, and Current Chapter are intentionally unchanged. The following checks confirmed zero diff against the merged baseline for their direct sources and shared content/layout dependencies:

• Education page
• Past Experience pages, archive, and content model
• Current Chapter page
• shared globals, site content, layout, and package manifests

SiteShell keeps its existing sidebar by default; only Home opts out. Rendered-output tests assert that all three protected routes still include the original profile sidebar.

Validation

• npm.cmd run check — passed
• static production build — 13/13 routes generated
• rendered artifact tests — 14/14 passed
• npm.cmd audit --omit=dev — 0 vulnerabilities
• git diff --check — passed
• responsive browser QA — desktop, 720px, 390px, and 320px
• no horizontal overflow; Home has one canvas, no sidebar, and a working scroll handoff

This PR is intentionally left as a draft for visual audit. main is unchanged.