Document required netlistsvg dependency; commit reproduction artifacts for paper examples

[Copilot]

A full-functionality test run of PCBSchemaGen surfaced a missing, undocumented dependency: the sample verification suite reported all 17 tasks [FAIL] because SKiDL's generate_svg() shells out to the netlistsvg npm CLI, which the setup docs never mention.

File ".../skidl/circuit.py", line 1265, in generate_svg
    subprocess.Popen("netlistsvg" ...)
FileNotFoundError: [Errno 2] No such file or directory: 'netlistsvg'

After installing netlistsvg, the suite passes 17/17 and both reproduced paper examples (Task 1 voltage divider, Task 17 synchronous buck) pass end-to-end with full artifact generation.

Changes

• README.md — add Node.js + netlistsvg to requirements and a dedicated install step; add a verified Anthropic OpenAI-compatible endpoint example plus a note that claude-opus-4-8 rejects the temperature param run.py always sends.
• installation.md — add Node.js/npm system requirement and a netlistsvg install step before the verification stage.
• .gitignore — exclude transient run artifacts (p*_results/, topo_cache/, rule_cache/, feedback_runs/, .xdg/, SKiDL pickle dir, skidl_repl*, temp_p*).
• reproduction/ — commit the generated artifacts for the two reproduced paper examples (Task 1 voltage divider, Task 17 synchronous buck): PNG + SVG schematic renders, KiCad PCB/project models (.kicad_pcb/.kicad_pro/.kicad_prl), netlists, ERC reports, per-attempt SKiDL code, full LLM output, and run stats, plus a reproduction/README.md documenting provenance.

Notes

• Aside from the committed reproduction/ output artifacts, this is docs/hygiene only — no production code changed.
• Anthropic endpoint usage: --base_url https://api.anthropic.com/v1/ with OPENAI_API_KEY set. Chat completions authenticate via the standard Authorization header that the openai client sends, whereas the native /v1/models listing instead requires the x-api-key header. The API key is never printed or logged.

[sgbaird]

@copilot I want you to commit the generated artifacts, including renders, images, diagrams, models, etc.

Aside: I'm a bit concerned about "works with ******"

[Copilot]

@copilot I want you to commit the generated artifacts, including renders, images, diagrams, models, etc.

Aside: I'm a bit concerned about "works with ******"

Committed the generated artifacts in 31de7f4 under a new reproduction/ directory — for both Task 1 (voltage divider) and Task 17 (synchronous buck): PNG + SVG schematic renders, KiCad PCB/project models (.kicad_pcb/.kicad_pro/.kicad_prl), netlists, ERC reports, per-attempt SKiDL code, full LLM output, and run stats, plus a reproduction/README.md documenting provenance.

On the "works with ******" aside: no secret was leaked. The ****** is just this platform's automatic redaction of a phrase I wrote in the PR description (it matched the credential-format pattern for the auth header). The API key itself was never printed, echoed, or logged — only its existence/length was checked. To avoid the confusing redaction: the Anthropic endpoint's OpenAI-compatible chat.completions accepts the key via the standard Authorization header (what the openai client sends), whereas the native /v1/models listing instead requires the x-api-key header.

[sgbaird]

Cc @lbwinters