Markup: add IDs to Clause 5 definitions

[UditDewan]

Summary

• Adds explicit IDs to the 12 definitions in Clause 5 that did not have one.
• Preserves existing variants and oldids metadata.
• Enables direct fragment links and references pane navigation for these terms.

Definitions

• chain production
• goal symbol
• Parse Node
• the same Parse Node
• covered
• abstract operations
• syntax-directed operation
• source text matched by
• runtime semantics
• static semantics
• values without identity
• value with identity

Validation

• npm run build
• Verified that each new ID appears exactly once in the source and rendered Clause 5 output.

Closes #3502

[nicolo-ribaudo]

Please read https://github.com/tc39/how-we-work/blob/main/AI_POLICY.md and clarify how it applies to this PR's description.