fix(ci): align protected file checks

[overtrue]

Summary

• replace the deleted docs/SPEC.md protected path with docs/reference/rc/
• add crates/core/src/config.rs to the CI protected-file list so it matches AGENTS.md
• remove stale SPEC.md wording from AGENTS.md

Validation

• ruby -e 'require "yaml"; YAML.load_file(".github/workflows/ci.yml")'
• simulated protected-file matching for docs/reference/rc/, crates/core/src/config.rs, and schemas/output_v1.json.bak
• git diff --check

[Copilot]

Pull request overview

This PR aligns CI protected-file enforcement with the current protected paths documented in AGENTS.md.

Changes:

• Replaces stale docs/SPEC.md references with docs/reference/rc/.
• Adds crates/core/src/config.rs to the CI protected-file list.
• Updates AGENTS guidance to refer to command reference documentation instead of SPEC.md.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
AGENTS.md	Updates protected-file documentation and removes stale SPEC.md wording.
.github/workflows/ci.yml	Updates protected-file checks to cover the command reference directory and core config file.

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