Fix stale tool references in porting guide

[tianma-if]

Fix stale tool references in porting guide

Base: obra/superpowers:dev
Head: msh01/superpowers:codex/fix-porting-guide-stale-tool-refs

Who is submitting this PR? (required)

Field	Value
Your model + version	GPT-5
Harness + version	Codex desktop app (exact app version not exposed in this session)
All plugins installed	Codex app tools exposed in this session, including GitHub, OpenAI bundled browser/chrome/computer-use, OpenAI primary runtime document/pdf/spreadsheet/presentation/template tools, Cloudflare, HeyGen, Hugging Face, Neon Postgres, Notion, Vercel, and local custom HyperFrames/media skills
Human partner who reviewed this diff	msh01

What problem are you trying to solve?

Issue #1873 identified stale Gemini-related references after Gemini CLI support was removed. docs/porting-to-a-new-harness.md still presents Gemini and references/gemini-tools.md as current copy-from references even though gemini-tools.md is no longer tracked. The same live reference table also names references/claude-code-tools.md and references/copilot-tools.md, which are not tracked in the current checkout.

What does this PR change?

Updates the porting guide so it no longer points at missing tool-reference files as current reference integrations. It keeps the important Shape C lesson: do not trust @-include expansion until a unique-marker test proves the content is present without a tool call.

Is this change appropriate for the core library?

Yes. This fixes core contributor documentation for harness porting and avoids directing contributors to files that are not present.

What alternatives did you consider?

I considered removing the whole Shape C section, but #1873 explicitly says to preserve the @-include-is-a-hint lesson because it matters for Gemini-derived harnesses such as Antigravity. This PR preserves that lesson while removing stale file references.

Does this PR contain multiple unrelated changes?

No. Every edit is in docs/porting-to-a-new-harness.md and addresses stale current-reference entries.

Existing PRs

• I have reviewed all open AND closed PRs for duplicates or prior art
• Related PRs: chore: remove unreferenced skill files, fix broken GEMINI.md import #1899 fixes GEMINI.md and removes orphaned files. This PR intentionally does not touch GEMINI.md; it handles the remaining porting-guide stale references from Finish removing Gemini CLI support: broken @-include + dangling doc refs (must not regress Antigravity) #1873.

Environment tested

Harness	Harness version	Model	Model version/ID
Codex desktop app	exact app version not exposed	GPT-5	GPT-5

New harness support (required if this PR adds a new harness)

Not applicable.

Evaluation

• Initial prompt: user asked to find real, high-quality contribution candidates for Superpowers.
• Eval sessions run after the change: 0; documentation reference fix only.
• Before/after: before, the porting guide referenced missing gemini-tools.md, claude-code-tools.md, and copilot-tools.md; after, those stale references are gone while the Shape C verification rule remains.

Verification run:

rg -n "gemini-tools|references/claude-code-tools|references/copilot-tools" docs/porting-to-a-new-harness.md README.md docs/testing.md skills tests .github -S || true
bash tests/hooks/test-session-start.sh
bash tests/kimi/run-tests.sh
bash tests/codex/test-marketplace-manifest.sh
git diff --check

Rigor

• Verified the referenced files are absent from the current checkout
• Avoided overlap with open PR chore: remove unreferenced skill files, fix broken GEMINI.md import #1899 by not touching GEMINI.md

Human review

• A human has reviewed the COMPLETE proposed diff before submission