Remove tracked generated build and report artifacts

[jjoonleo]

Problem

Tracked generated output is checked into the repository, including coverage reports, iOS build cache files, Firebase hosting cache files, and Widgetbook Firebase hosting build output. These artifacts are machine-generated, inflate repository size and diff noise, and can become stale relative to source and CI output.

Evidence

Read-only git ls-files inventory found tracked generated artifacts under:

• coverage/
• ios/build/
• .firebase/
• widgetbook/.firebase/

The largest bucket is Widgetbook Firebase hosting output. Current ignore rules do not cover these paths consistently.

Proposed direction

Remove these generated artifacts from git tracking with git rm --cached, keep local files untouched, and add ignore rules for the generated paths. Keep source-controlled config files separate from deploy/build outputs so Firebase, coverage, iOS, and Widgetbook artifacts are regenerated locally or in CI instead of committed.

Acceptance criteria

• git ls-files -- coverage ios/build .firebase widgetbook/.firebase returns no tracked files.
• .gitignore and/or widgetbook/.gitignore prevent the same generated artifact paths from being re-added.
• Required source/config files remain tracked.
• flutter test --coverage and Widgetbook/Firebase build or deploy flows can regenerate their outputs without requiring committed artifacts.

Source: Codex codebase audit on 2026-06-28.