The repository

LocalDrive/
  server/        the Go backend, which is the product
  localdrive/    the Flutter client, one codebase for every platform
  docs/          this documentation
  landing/       the website, which reads docs/ directly
  README.md

The backend

server/
  cmd/localdrive/     the one entry point
  internal/
    runner/           every mode the binary runs in
    config/           environment loading and validation
    httpapi/          chi routes and handlers
    auth/             passwords, tokens, sessions, invites, 2fa, recovery
    files/            the node tree, access resolution, maintenance
    shares/           public links and account to account grants
    libraries/        storage roots, disk stats, offline detection
    storage/          the content addressed object store and the browse mirror
    uploads/          the tus DataStore
    thumbnails/       generator dispatch and capability probing
    ws/               the hub, clients, event types
    jobs/             worker pool and scheduler
    db/               sqlite setup, migrations, the writer goroutine
    audit/            the activity log
    middleware/       recovery, logging, cors, rate limiting
    models/           row shapes shared by every package
  pkg/
    pathsafe/         canonicalization and traversal guard, tested in isolation
    checksum/
  migrations/

Conventions

Shared logic lives in one place. A validation rule, a formatter, or a widget is not written twice.
Add abstraction when a second concrete use case needs it, not before.
Every user facing string goes in both app_en.arb and app_ar.arb, checked against l10n/glossary.md first.
Comments explain why, not what. If a comment restates the line below it, cut it.