docs: align developer instructions and CI sequences across documentation

[numnx]

This PR resolves inconsistencies across our primary instruction files (AGENTS.md, CLAUDE.md, GEMINI.md, README.md, and the docs/ and docs-web/ trees).

Specifically:

• Asserts the deterministic pnpm run ci verification chain without erroneously listing internal guardrail/audit scripts.
• Refines pnpm run dev semantics where it was implied to only start the backend.
• Cements the fork branch policy where origin matches the numnx/codeux fork.
• Incorporates the explicit docs/ mirror-to docs-web/ workflow standards.

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PR created automatically by Jules for task 7639111637287380126 started by @numnx

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