refactor: move dbt doc fragments to docs/data/

Separates dbt documentation fragments from human-facing docs by moving
them to docs/data/ and updating docs-paths configuration.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: themightychris

dbt_project.yml

@@ -7,7 +7,7 @@ profile: 'gtfsrt_sandbox'
 model-paths: ["models"]
 seed-paths: ["seeds"]
 macro-paths: ["macros"]
-docs-paths: ["docs"]
+docs-paths: ["docs/data"]
 target-path: "target"
 clean-targets:
   - "target"