Adds a companion-docs header and inline ADR jumps on every load-bearing
choice (ADR-001 runtime, ADR-002 UI, ADR-004 git kill-switch, ADR-006
concurrency, ADR-007 storage, ADR-009 USB-host gate). Render module
also points at qfd §3 to anchor "why these functions rank top."
Strip-aspect 5.79" panel (792×272) replaces the page-shaped 7.5" choice.
Reflows the v0.1 screen layout, framebuffer memory budget, and spike 2
acceptance to validate the SSD1683-class controller path or fall back to
a ~300 LoC custom embedded-hal driver.
