feat(hardware): add topology-first semantic gate v0.1

[11cookies11]

Summary

Adds the first full v0.1 implementation slice of the topology-first hardware agent methodology.

This PR introduces a sidecar Hardware Semantic Layer that runs after build-ir / validate-ir intent and before KiCad export. It is designed to catch incomplete hardware topology that KiCad ERC may not understand, such as load switches without VIN/VOUT, charger program pins left unresolved, USB-C sink CC pins without Rd, and module-specific display pins that need explicit strategy.

Added

• scripts/hardware_semantic_gate.py

  • Reads source/circuit-model.source.json
  • Derives:
    • build/net-intents.v1.json
    • build/pin-contracts.v1.json
    • build/hardware-erc.v1.json
    • build/export-gate.v1.json
  • Returns non-zero when BLOCKER findings exist unless --no-fail is used.

• Native export enforcement:

  • hwtool agent export-kicad --project . runs the semantic gate first.
  • Export is blocked when build/export-gate.v1.json says block_export_kicad.

• Sidecar schemas:

  • schemas/pin-contracts.v1.json
  • schemas/net-intents.v1.json
  • schemas/hardware-erc.v1.json
  • schemas/export-gate.v1.json

• Rule pack:

  • resources/hardware-rules/hardware-semantic-rules.v0.1.yaml

• Methodology docs:

  • docs/hardware-semantic-layer-v0.1.md
  • docs/agent-prompts/hardware-design-agent-v0.1.md

• Regression tests:

  • tests/hardware_semantic/test_hardware_semantic_gate.py
  • CLI tests for export blocking and dry-run behavior

P0 rule coverage

• TPS22918-style load switches
• BQ24074-style charger + power-path ICs
• USB-C USB2 Sink connectors
• SPI e-paper display connectors

Intended flow

hwtool agent build-ir --project .
hwtool agent validate-ir --project .
hwtool agent export-kicad --project .

For diagnosis, the standalone gate remains available:

python scripts/hardware_semantic_gate.py --project .

CI notes

The pipeline job now runs the semantic gate / CLI / artifact validation tests that are stable on a clean GitHub runner, and validates the committed e2e fixture artifacts instead of a stale example pipeline path.