feat: add settings.local.json support for Claude Code integration

[CorticalCode]

Summary

Adds settings.local.json support to the Claude Code integration layer. Fixes #276.

• When settings.local.json exists, the TUI install flow lets users choose which file to target
• Detection functions check both files, matching Claude Code's merge precedence (local wins)
• Uninstall cleans both files but only removes entries ccstatusline owns (isKnownCommand guard)
• Hook sync targets the file where the statusLine lives, cleans stale hooks from the other

Design decisions

1. Auto-detect: If settings.local.json exists on disk, prompt the user to choose a target. If it doesn't exist, default behavior is unchanged — zero friction for the common case.
2. Local wins: settings.local.json takes precedence when checking installation status, matching Claude Code's own merge semantics.
3. Ownership guard: Uninstall only removes statusLine entries identified by isKnownCommand(). A company-managed or user-custom statusLine in either file is never touched.
4. Accurate display: Confirmation dialogs show the actual file being targeted. A warning appears if installing to settings.json while settings.local.json already has a statusLine that would take precedence.

Files changed

• src/utils/claude-settings.ts — filePath param on load/save, private resolveStatusLine() for dual-file precedence, ownership-guarded uninstall
• src/utils/hooks.ts — file-aware hook sync targeting active file, stale hook cleanup from non-active file
• src/tui/components/FileTargetSelect.tsx — new component for install target selection
• src/tui/App.tsx — install flow integration, fileTarget screen, confirmation warnings
• src/tui/components/InstallMenu.tsx — localSettingsDetected prop for contextual help text
• Tests for all new behavior including path traversal, malformed files, ownership preservation

Known limitations

• If settings.json is read-only (e.g., company-managed with restrictive permissions), write operations that target it will error. The settings.local.json support provides a workaround.
• Related but not in scope: PR feat(settings): Add support for local/project settings #58 by @jackall3n (project-level ccstatusline settings) addresses a different settings layer.

Test plan

• Install to settings.json (default, no settings.local.json present) — unchanged behavior
• Install when settings.local.json exists — FileTargetSelect screen appears
• Install to settings.local.json — writes only to local file
• Uninstall with entries in both files — removes ccstatusline entries, preserves non-ccstatusline entries
• Hook sync after install to local file — hooks written to local, cleaned from global

🤖 Generated with Claude Code