feat(cli): add --private flag for login-gated share links

[abhinav-1504]

What

Adds --private flag to the analyze command. When passed alongside
--share, the upload request includes X-Optiqor-Private: 1 so the
sandbox receiver can return a login-gated URL (backend Phase 2 work).

Why

Fixes #23

How

• Registered --private bool flag on analyze next to --share
• Fails closed: --private without --share returns an error
• share.Upload() accepts a new private bool param and conditionally
  sets X-Optiqor-Private: 1 on the POST request
• Printed suffix changes to (uploaded · login-gated) when private=true
• Honours offline mode — no upload attempted when sandbox is unreachable

Testing

• go test ./internal/share/... -v — 11/11 PASS
• go build ./... — clean
• Tested locally with ./cmd/optiqor/demo/values.yaml:
  • --share alone → URL printed
  • --private alone → error returned
  • --share --private → URL printed with login-gated suffix
  • --help → --private flag listed correctly

Checklist

• PR title follows Conventional Commits (feat(scope): subject)
• No unrelated changes pulled in
• No LLM calls or telemetry introduced
• No proprietary backend imports

[github-actions]

First PR — welcome aboard!

A few things to expect:

1. CI: every PR runs build + race tests + lint on Ubuntu and macOS. If something fails, the log will tell you exactly which gate.
2. DCO: every commit needs Signed-off-by:. git commit -s adds it automatically.
3. Conventional Commits: PR titles like feat(analyze): new rule or fix(cli): handle X. We squash-merge by default.
4. Review: a maintainer will review within 72 hours. Suggestions are conversations, not orders — push back if something doesn't fit your context.

If you get stuck, reply here or jump to Discussions. We want this PR to land.

[abhinav-1504]

Hello @btwshivam, Ready for review. All CI checks pass and DCO is signed.
Tested locally:

• --share alone ->URL printed
• --private without --share -> error returned (fails closed)
• --share --private -> URL printed with login-gated suffix
• 11/11 unit tests pass including two new ones for the private header

[abhinav-1504]

Hi @btwshivam , just following up on this PR. All CI checks are passing and the implementation has been tested locally as mentioned above.

Could you please take another look when possible? Thanks.

[abhinav-1504]

Hi @btwshivam, resolved the merge conflicts and force-pushed. Branch is clean and all checks are passing. Ready for review.