Heatsinks, wider 12 V tracks, design review; pause project

- PCB rev 0.1: Power3A class (1.5 mm) for the 12 V input path, Aavid
  clip-on heatsinks on Q3/Q5/Q6 (project footprint library), T-junction
  healing and via shrink in the router; DRC 0 errors
- Current-capacity and heatsink documentation
- CLAUDE.md with project decisions, workflow and gotchas
- docs/design-review.md: review of a module-only PSU (rev 0.2) and cost
  estimate
- Project paused for budget and safety reasons

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

README.md

@@ -24,11 +24,16 @@ Stern/Sega display PSU (520-5138-00). The original transformer and AC front end
 | [docs/safety.md](docs/safety.md) | Safety design (HV watchdog, fusing, layout, bring-up procedure) |
 | [docs/esp32-interface.md](docs/esp32-interface.md) | ESP32 pin plan, 74HCT245 level shifter, panel signals |
 | [docs/bom.md](docs/bom.md) | Bill of materials |
+| [docs/design-review.md](docs/design-review.md) | Design review of the module-only PSU (rev 0.2) and cost estimate |
 | [reference/](reference/) | Original Stern 520-5138-00 display PSU schematic |
 | [firmware/](firmware/) | PlatformIO project for the ESP32 |
+| [CLAUDE.md](CLAUDE.md) | Project notes for Claude: decisions, workflow, tool paths, gotchas |
 
 ## Status
 
+> **Paused (2026-10-24)** because of budget and safety concerns. See [docs/design-review.md](docs/design-review.md)
+> for the latest review and cost estimate.
+
 - [ ] Identify panel: manufacturer/part number from its label
 - [ ] Map the panel's power connector pins (WPC panel ≠ Stern CN2 pinout) and check if +12 V is used
 - [ ] Map the panel's 14-pin data connector