fix: comment out placeholders in CAMARA_common.yaml for $ref consumption

[hdamker]

What type of PR is this?

• correction

What this PR does / why we need it:

Comments out {{SPECIFIC_CODE}} and {{field}} placeholder patterns in Generic error responses (400, 403, 404, 409, 422) of CAMARA_common.yaml. The commented lines remain as human-readable documentation for API developers, while the file becomes directly consumable via $ref by bundling tools, Spectral, and YAML parsers.

This unblocks $ref-based consumption of common schemas as discussed in #577 and the bundling design in ReleaseManagement#436.

Three types of placeholder occurrences are commented out:

1. Enum values — - "{{SPECIFIC_CODE}}" in code enums (5 responses)
2. Example blocks — GENERIC_4xx_{{SPECIFIC_CODE}}: entries with their value blocks (5 responses)
3. Example message — "{{field}} is not consistent with access token." (1 occurrence in Generic403)

Which issue(s) this PR fixes:

Fixes #601

Does this PR introduce a breaking change?

• Yes
• No

Special notes for reviewers:

• YAML validation and Spectral linting pass cleanly (0 errors, only pre-existing unused-component warnings)
• 38 lines changed, line count preserved (comment prefix added, no lines deleted)
• API-specific error code extension patterns (allOf, property override, etc.) are a separate topic (Establish guidance for consuming schemas from CAMARA_common.yaml #577)
• Thanks and credits to @rartych for the idea and testing it in a PoC

Changelog input

fix: comment out placeholder patterns in CAMARA_common.yaml to enable $ref consumption

Additional documentation

Related design: ReleaseManagement#436 (section 8.1)

[PedroDiez]

LGTM

[rartych]

If we want to use yamllint for artifacts (for now no linting is implemented in Commonalities) then we need to consider that
the implementation of comments-indentation rule in yamllint is buggy:

  326:13    error    comment not indented like content  (comments-indentation)
  391:13    error    comment not indented like content  (comments-indentation)
  430:13    error    comment not indented like content  (comments-indentation)
  537:13    error    comment not indented like content  (comments-indentation)
  665:13    error    comment not indented like content  (comments-indentation)

https://yamllint.readthedocs.io/en/stable/rules.html#module-yamllint.rules.comments_indentation

The quick fixes are:

• to start each comment line # with the same indentation as the line above the comment (line 325 in the first case)

                message: Client specified an invalid range.
                # GENERIC_400_{{SPECIFIC_CODE}}:
                #   description: Specific Syntax Exception regarding a field that is relevant in the context of the API
                #   value:
                #     status: 400
                #     code: "{{SPECIFIC_CODE}}"
                #     message: Message for specific code

• or disable the rule by adding comment :

# yamllint disable rule:comments-indentation

https://yamllint.readthedocs.io/en/stable/disable_with_comments.html#disabling-checks-for-all-or-part-of-the-file