UI shows hardcoded "/ 10 GB" project storage cap; backend hard-rejects files > 10 GB

[ravirajsinh45]

Reported by @ducknoodledance in #61.

Problem

The project detail page shows a "Storage X / 10 GB" indicator, and the
backend rejects any single upload larger than 10 GB. Both limits are
hardcoded and there is no per-org / per-project quota field in the DB,
so a self-hoster running on their own S3 / MinIO has no way to change
or remove them. The UI text in particular is misleading — it implies a
quota that doesn't actually exist as a configurable concept.

Where it lives

• Frontend denominator (cosmetic): apps/web/app/(dashboard)/projects/[id]/page.tsx:592

  const limit = 10 * 1024 * 1024 * 1024; // 10 GB default limit

  rendered as Storage {used} / {limit} (lines 600–606).
• Backend per-file ceiling: apps/api/schemas/upload.py:15

  MAX_FILE_SIZE_BYTES = 10 * 1024 * 1024 * 1024  # 10 GB

  enforced in apps/api/routers/upload.py and apps/api/routers/assets.py
  ("File exceeds 10GB limit").
• Project / Organization models have no storage_limit column and
  ProjectResponse exposes only storage_bytes (used), not a limit.

Proposed fix

• Drop the hardcoded denominator from the UI, or drive it from an
  optional storage_limit field that's only shown when set.
• Make MAX_FILE_SIZE_BYTES configurable via env (e.g.
  MAX_UPLOAD_BYTES, default unlimited or a high sane value).
• Optionally add a per-org/per-project quota for operators who do
  want a cap.