Feature: configurable output directory

[guillempuche]

First off, thanks for creating this tool! It's exactly what's needed for giving AI agents deeper context beyond types. The lockfile version matching is particularly clever. 🙏

Problem

The output directory is hardcoded as opensrc/. In monorepos that already organize library references in a different location (e.g., docs/ for git subtrees), having a separate opensrc/ folder creates fragmentation.

Use case

Our monorepo uses docs/ for library source references:

docs/
├── effect/          # git subtree
├── tamagui/         # git subtree
└── better-auth/     # git subtree

We'd like opensrc-fetched sources to live alongside:

docs/
├── effect/          # git subtree
├── tamagui/         # git subtree
├── better-auth/     # git subtree
└── opensrc/         # or directly: expo-router/, @effect--platform/, etc.

Proposal

Add a --output flag or config option in settings.json:

yarn opensrc effect --output docs/opensrc

Or in opensrc/settings.json:

{
  "outputDir": "docs/opensrc"
}

The tool would need to update the paths it writes to .gitignore, tsconfig.json, and AGENTS.md accordingly.

Workaround

Currently using a symlink (ln -s docs/opensrc opensrc), but native support would be cleaner.