Update safe outputs spec with templatable boolean and integer fields

[Copilot]

The safe outputs specification didn't document that several configuration fields accept GitHub Actions expressions (e.g., ${{ inputs.max-issues }}) in addition to literal values — a capability already supported in the implementation.

Changes

• GP1 / TS2 footer: Updated syntax to true | false | <github-expression>
• TS1 max: Updated syntax to <positive-integer> | -1 | null | <github-expression>; added expression bullet to Special Values
• New §5.5 — Templatable Fields: Formalizes the concept with conformance requirements for both field categories:
  • Templatable integers (max): expression resolved at runtime as integer; non-integer result MUST fail
  • Templatable booleans (footer, group, close-older-issues, hide-older-comments, close-older-discussions, draft, allow-empty, auto-merge, report-as-issue, unassign-first): free-form strings rejected at compile time; non-boolean runtime value treated as false
• Appendix F: Version bump to 1.14.0

create-issue:
  max: ${{ inputs.max-issues }}       # templatable integer
  group: ${{ inputs.group-issues }}   # templatable boolean
  footer: ${{ inputs.enable-footer }} # templatable boolean

Original prompt

Update safe output spec with templetable Boolean and integer fields

See recent commits with support for templetables

Custom agent used: w3c-specification-writer
AI technical specification writer following W3C conventions and best practices for formal specifications

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[Copilot]

Pull request overview

This PR updates the Safe Outputs MCP Gateway Specification to document that several configuration fields support GitHub Actions expressions (e.g., ${{ inputs.max-issues }}) in addition to literal values—a feature already present in the implementation but previously undocumented.

Changes:

• Added new Section 5.5 "Templatable Fields" with formal conformance requirements for templatable integers and booleans
• Updated syntax definitions for footer (GP1, TS2) and max (TS1) to include <github-expression> alternative
• Added version 1.14.0 entry to Appendix F documenting these changes

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[Copilot]

The document version header needs to be updated to 1.14.0 to match the version history added in Appendix F. Currently the header shows version 1.13.0 but Appendix F documents this as version 1.14.0.