[ctawiah]

Context

JSON, YAML, and TOML sources need lossless scalar updates and explicit read-only behavior.

What changes

• Add exact-span JSON parsing.
• Add YAML scalar updates and safety rules.
• Add TOML scalar and string-family updates.
• Add malformed-input, conformance, round-trip, and fuzz tests.

select: 'tools[name="lookup"]'
map:
  description: description

Design notes

• Structural insertion and deletion remain read-only.
• YAML aliases, merges, tags, and block scalars remain read-only.

Review focus

• Do accepted edits preserve surrounding bytes?
• Do duplicate keys fail before any edit?

Verification

• make build
• go test ./...
• Repository lint
• Relevant race tests

Related changes

1. ctawiah/sync-projection-core-3bbf: projection and problem core
2. ctawiah/sync-reference-core-3bbf: reference registry and Markdown
3. This PR: structured adapters
4. ctawiah/sync-provider-profiles-3bbf: provider profiles
5. ctawiah/sync-python-adapter-3bbf: Python adapter
6. ctawiah/sync-typescript-adapters-3bbf: TypeScript and JavaScript adapters
7. ctawiah/sync-descriptor-storage-3bbf: descriptor storage
8. ctawiah/sync-source-publication-3bbf: source compilation and publication
9. ctawiah/sync-source-planner-3bbf: planner integration
10. ctawiah/sync-descriptor-detach-3bbf: descriptor detach
11. ctawiah/sync-link-preparation-3bbf: link preparation
12. ctawiah/sync-link-command-3bbf: link commands
13. ctawiah/sync-reference-cleanup-3bbf: Phase 1 cleanup