Deprecate Branch.has_schema_changes use Branch.schema_differs_from_default_branch

[ogenstad]

Why

Closes

What changed

How to review

How to test

# Commands to validate

Impact & rollout

• Backward compatibility:
• Performance:
• Config/env changes:
• Deployment notes:

Checklist

• Tests added/updated
• Changelog entry added (uv run towncrier create ...)
• External docs updated (if user-facing or ops-facing change)
• Internal .md docs updated (internal knowledge and AI code tools knowledge)
• I have reviewed AI generated content

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Summary by cubic

Adds the full spec and implementation plan to deprecate Branch.has_schema_changes and introduce schema_differs_from_default_branch, clarifying the field’s meaning while keeping a non-breaking path. This documents IFC-2281 and prepares backend, GraphQL, and UI changes; no runtime code changes are included in this PR.

• New Features
  • Defines the GraphQL contract: add schema_differs_from_default_branch on Branch and InfrahubBranch; deprecate has_schema_changes with a reason naming the replacement and removal in 1.14.0, with strict value parity.
  • Plans a backend model property (schema_differs_from_default_branch) with the old property delegating to it; internal readers move to the new name; no logic changes.
  • Plans frontend updates to query the new field and replace misleading copy with “schema differs from default”; includes schema/codegen regen and tests.
  • Provides quickstart, tasks, and tests to verify parity, introspection deprecation, and UI usage; includes changelog fragments and follow-up tickets for SDK adoption and the 1.14.0 removal.

^{Written for commit 2c60fe8. Summary will update on new commits.}

[cubic-dev-ai]

No issues found across 8 files

Confidence score: 5/5

• Automated review surfaced no issues in the provided summaries.
• No files require special attention.

<sub>Shadow auto-approve: would auto-approve. Specification-only PR adding design documents, plans, and contracts for a future rename. No runtime code, config, or operational changes; change is bounded and clearly beneficial for planning and communication.

Re-trigger cubic</sub>