fix(init): skip installed deps, isolate install failures, pre-select prompt defaults

[robdmoore]

What & why

verifyx init had three real-world failure modes reported in practice. This makes it robust to all three.

1. Dependency installs conflicted or bumped existing versions

The install was a single atomic npm install --save-dev <all deps>. One peer-dependency conflict (e.g. oxlint + oxlint-tsgolint) failed the whole batch so nothing installed, and re-running could bump an already-present typescript.

• New src/scaffold/installDeps.ts skips any dep already declared in package.json (deps/dev/peer/optional) or present in node_modules — an existing typescript/oxlint is left untouched (no version bump), and known peer conflicts are sidestepped when the tool is already there.
• Missing deps install in one fast batch; on failure it falls back to per-package installs to isolate the culprit(s), installs the rest, and reports exactly what to install manually at the end instead of aborting.

2. A failing install appeared to prevent the .claude files

Scaffolding was always written before the install, but its confirmation printed after, so a wall of npm errors (or a Ctrl-C on a hanging install) hid it. The scaffold report now prints before the install is attempted — the .claude/CLAUDE.md output can no longer be hidden or blocked by the install.

3. Interactive prompts silently dropped selections

enquirer's multiselect ignores each choice's enabled for the submitted result — it paints a √ but a plain Enter returns []. So selecting the pre-checked Claude target (and the recommended checks) and hitting Enter wrote nothing. Fixed by passing the enabled names as initial, which actually pre-selects them.

Testing

• src/scaffold/installDeps.test.ts — happy-path batch, skip-declared, skip-node_modules, all-present no-op, and batch-fail isolation.
• src/commands/registerInit.test.ts — preSelected returns the enabled choice names.
• Manually verified end-to-end in scratch projects (.claude/CLAUDE.md written up-front) and confirmed the enquirer initial behaviour against the exact enquirer.prompt({...}) call shape.
• verifyx all (lint, format, types, complexity, tests) green.

Note: an enabled-alone-returns-[] integration test against live enquirer was intentionally dropped — it's flaky under vitest's headless (non-TTY) environment where initial is applied async during render. The interactive path only ever runs with a TTY (the non-TTY path skips enquirer entirely), so this is a harness artifact, not a coverage gap.

🤖 Generated with Claude Code