👷 exclude worktree directories from linting and formatting

[bcaudan]

Motivation

Worktree directories (.worktrees/ and .claude/worktrees/) were being picked up by ESLint and Prettier, causing noise during checks. These directories contain isolated workspaces unrelated to the project source.

Changes

• Add .worktrees/** to ESLint ignores in eslint.config.mjs
• Add .worktrees and .claude/worktrees to .prettierignore

Test instructions

Run yarn lint and yarn format:check — neither should scan files inside .worktrees/ or .claude/worktrees/.

Checklist

• Tested locally (playground)
• Added unit tests for this change.
• Added e2e/integration tests for this change.
• Updated related documentation.
• Agentic code review findings addressed or explicitly dismissed.

[Copilot]

Pull request overview

PR Review — Score: 4.9 / 5

I would approve this change. It cleanly removes lint/format noise by excluding worktree directories from ESLint and Prettier, without affecting source code or build outputs.

Why 4.9: Minimal, targeted ignore patterns; consistent with existing ESLint ignore strategy (e.g., .claude/**, dist, coverage); low regression risk.

Why not 5: No automated check specifically asserting these ignore behaviors (understandable for a tooling-config tweak, but it does mean the behavior relies on manual verification).

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Findings

Severity	Item
Minor	No blocking issues found — Changes are straightforward and align with the PR motivation.

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Architectural flow

flowchart TD
  A[Developer runs yarn lint / yarn format:check] --> B[Tool enumerates files from repo root]
  B --> C{Path matches ignore patterns?}
  C -->|Yes| D[Skip file/dir]
  C -->|No| E[Analyze/format file]
  D --> F[Less noise + faster checks]
  E --> F

Loading

Before: ESLint/Prettier would discover and process files inside .worktrees/ (and Prettier could also process .claude/worktrees/), producing unrelated warnings/errors.

After: ESLint ignores .worktrees/** via flat-config ignores, and Prettier ignores .worktrees and .claude/worktrees via .prettierignore, preventing worktree content from being scanned.

Changes:

• Add .worktrees/** to ESLint ignore patterns.
• Add .worktrees and .claude/worktrees to Prettier ignore patterns.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
eslint.config.mjs	Excludes .worktrees/** from ESLint file traversal to avoid linting isolated workspaces.
.prettierignore	Prevents Prettier from formatting/checking worktree directories (.worktrees, .claude/worktrees).