Remove all non-org-scoped API endpoints

[dcramer]

Summary

Most project-scoped endpoints in src/api/mod.rs have no formal deprecation marker in the Sentry API. Sentry does have a @deprecated decorator with active brownouts, but it has only been applied to alert rule endpoints so far. This migration is preferred but not urgent for most items.

Preferred migration (not formally deprecated)

• list_releases() — /projects/{org}/{project}/releases/ → /organizations/{org}/releases/ (already used when project is None; remove the project-specific branch)
• list_organization_project_events() — /projects/{org}/{project}/events/?cursor={} → /organizations/{org}/events/ (add project as query param)
• list_organization_project_issues() / bulk_update_issue() — /projects/{org}/{project}/issues/?... → /organizations/{org}/issues/ (add project as query param)

No org-scoped equivalent exists yet

Tracked in getsentry/sentry#118963:

assemble_difs (/projects/{org}/{project}/files/difs/assemble/), assemble_build (/projects/{org}/{project}/files/preprodartifacts/assemble/), snapshot creation and upload-options.

[linear-code]

CLI-342