feat: add shared Insights Snowflake routing foundation

[santhosh-apphelix-2u]

Summary

• Add a global insights_snowflake_enabled Waffle flag helper for the remaining Insights Snowflake migration.
• Keep the existing course activity flag working, while allowing the new global flag to also route activity through Snowflake.
• Add a shared response header helper for X-Insights-Data-Source.
• Update course activity to use the shared helper instead of keeping header logic inside the view.
• Add focused unit coverage for the new flag and response header behavior.

Notes

This PR is foundation only. It does not migrate additional Insights APIs yet.

[Copilot]

🟢 Approval recommended

The changes are cohesive, maintain backward compatibility for the course activity flag, and include targeted unit coverage for the new shared behaviors.

Pull request overview

This PR lays the groundwork for routing Insights APIs to Snowflake by introducing a global Waffle flag helper and a shared response-header mixin, then wiring the existing course activity endpoint to use those shared utilities while preserving current endpoint-specific flag behavior.

Changes:

• Added insights_snowflake_enabled global toggle helper and updated course-activity routing to allow either the global or endpoint flag to enable Snowflake.
• Introduced InsightsDataSourceResponseMixin to consistently set X-Insights-Data-Source and updated course activity to use it.
• Added unit tests covering the new global flag helper, combined-flag behavior, and response-header mixin behavior.

File summaries

File	Description
analytics_data_api/v0/views/courses.py	Adopts the shared response-header mixin and uses shared setters for data-source attribution.
analytics_data_api/tests/test_insights_snowflake.py	Adds focused unit coverage for the new mixin and global flag behavior.
analytics_data_api/insights_snowflake/toggles.py	Introduces the global Snowflake enablement flag and composes it with the course-activity flag.
analytics_data_api/insights_snowflake/response_headers.py	Adds shared constants + mixin for setting X-Insights-Data-Source consistently.

Review details

• Files reviewed: 4/4 changed files
• Comments generated: 0
• Review effort level: Lite

---

💡 Add a code-review agent skill or configure MCP servers for context-aware, tailored reviews. Learn more in the docs.

[github-actions]

Coverage report

Click to see where and how coverage changed

File	Statements	Missing	Coverage	Coverage (new stmts)	Lines missing
analytics_data_api/insights_snowflake
response_headers.py
toggles.py
analytics_data_api/tests
test_insights_snowflake.py
analytics_data_api/v0/views
courses.py
Project Total

This report was generated by python-coverage-comment-action