DoC-13337-add-special-characters-data-modeling

[iamfortune]

Docs Issue: DOC-13337

PR to add special characters to SGW data modelling page

Preview URL:
https://preview.docs-test.couchbase.com/docs-sync-gateway-DOC-13337-add-special-characters-data-modelling

You will need the Docs Team credentials on Confluence.

[iamfortune]

@bbrks I have a few questions related to this PR

1. Does this escaping apply to the document _id, or only to property names/values inside the JSON body? This determines whether the note stays scoped to the "Value" subsection or needs to touch the "Key" section too.

2. Does escaping apply to property names (JSON keys) as well as values, or values only? The wording "property name or value" in my draft is only correct if this is confirmed either way.

3. Is <, >, & the complete list, or are other characters (", \, non-ASCII) also escaped? If the list is incomplete, the docs teach readers to expect a subset of what actually happens.

4. When a client reads the document back, does Sync Gateway return it still escaped, or does it unescape automatically before returning? This decides whether the "use a JSON deserializer or match the escaped form" guidance is accurate or backwards.

5. Does this escaping apply identically across all three write paths (Couchbase Lite SDKs, Sync Gateway REST APIs, Couchbase Server SDKs with shared bucket access), or are there exceptions per path? I reused this list from Property Naming without confirmation it holds here too.