feat(cli): Bitbucket foundation for unified Atlassian login #911

Component/Module

Integrations (Jira/Linear/Confluence/Sentry/GitHub)

Feature Type

New Integration

Problem Statement

Potpie needs a unified Atlassian CLI experience — one onboarding path for Jira, Confluence, and Bitbucket — instead of treating each product as a separate integration story.

Today the CLI supports Jira and Confluence auth, but Bitbucket is not wired in:

No Bitbucket credential storage alongside other Atlassian products
No way to connect Bitbucket as part of a future potpie atlassian login / logout flow
No CLI to list workspaces, repos, or pull requests after connect
This issue covers the first step: add Bitbucket as a first-class integration (auth, credential storage, token verification, and potpie bitbucket commands) so a follow-up PR can add potpie atlassian login|logout|status orchestrating Jira → Confluence → Bitbucket in one flow.

Standalone potpie jira / potpie confluence / potpie bitbucket commands remain as fallbacks.

Proposed Solution

Add Bitbucket Cloud as a first-class CLI integration so it can plug into a later unified Atlassian flow:

Credential layer — Store Bitbucket API tokens (keychain/file) alongside Jira and Confluence, with get_integration_status("bitbucket") support.

API clients — Verify scoped Bitbucket tokens and read workspaces, repositories, and pull requests via the Bitbucket Cloud API.

CLI commands — Expose standalone commands:

potpie bitbucket login / logout
potpie bitbucket ls / select

Existing potpie jira and potpie confluence commands stay unchanged. The unified potpie atlassian command ships in a follow-up PR stacked on this one.

Use Case

A user who only needs Bitbucket runs potpie bitbucket login, then potpie bitbucket ls and potpie bitbucket select to pick a workspace/repo and view pull requests.
On re-login, already-connected products are skipped so users can add Bitbucket without re-authenticating Jira and Confluence.

Alternatives Considered

No response

Additional Context

No response