new-fude-feature

name	new-fude-feature
description	Scaffold a new opt-in feature for the fude crate following the with_* builder convention — new module in src/, App::with_<feature> method, integration tests in tests/, inline tests only for private helpers. Use when adding a new capability like with_tray, with_updater, etc.

new-fude-feature

Scaffolds a new opt-in feature following fude's "narrow on purpose" convention.

Invariants to preserve

• Public surface grows only through App::with_<feature>(...) — never a free function.
• Errors return Result<_, String>; no thiserror.
• Public API → tests in tests/<feature>.rs. Private helpers → inline #[cfg(test)] mod tests.
• No new top-level dependency unless there is no reasonable alternative; if added, it must be ≥14 days old (see CLAUDE.md).

Steps

Given a feature name <feat>:

1. TDD first. Create tests/<feat>.rs with failing tests for the public contract. Run cargo test --test <feat> and confirm red.
2. Create src/<feat>.rs. Expose only the types / functions the test file needs.
3. Wire into src/lib.rs: mod <feat>; and add pub fn with_<feat>(mut self, ...) -> Self on App.
4. Make tests green. Keep diffs minimal.
5. If the feature touches the sandbox (FS, paths, PTY, external binaries), add a section to tests/<feat>.rs that exercises the symlink-escape / allow-list invariants.
6. Run the full gate: cargo fmt --check && cargo clippy --all-targets -- -D warnings && cargo test --all-targets && cargo test --doc.
7. Add a CHANGELOG.md entry under [Unreleased].

Anti-patterns (reject)

• Adding pub items that aren't reachable from an App::with_* method.
• Re-exporting third-party types at the crate root.
• Catch-all error enums. Return Err("short reason".into()).
• Mocking the filesystem in tests — use tempfile (already in dev-deps) or $HOME/.fude-test-scratch on macOS (/tmp canonicalizes and trips the sandbox).