fix(ci): skip scheduled workflows on forked repositories

[wayyoungboy]

Summary

• Forked repos lack required secrets (QWEN_API_KEY, SILICONFLOW_*_API_KEY, PROJECT_ACCESS_TOKEN),
  causing daily CI failures and noisy email notifications for all fork maintainers.
• Gate schedule and push events in regression.yml on github.repository == 'oceanbase/powermem' so
  fork repos silently skip instead of failing.
• Apply the same guard to sync-project-milestones.yml.
• Fix stale project URLs in pyproject.toml and docs/development/overview.md:
  • powermem/powermem → oceanbase/powermem (3 URLs)
  • https://powermem.readthedocs.io → https://www.powermem.ai/docs (2 occurrences, readthedocs
    returns 404)

Changed files

File	Change
.github/workflows/regression.yml	schedule/push gated on upstream repo; workflow_dispatch and
pull_request_target unchanged
.github/workflows/sync-project-milestones.yml	All jobs gated on upstream repo
pyproject.toml	Fix [project.urls] — Homepage, Repository, Issues, Documentation
docs/development/overview.md	Fix readthedocs link

Motivation

Every fork of this repo receives daily failure emails from the Regression Tests and Sync Project with Milestones workflows. These workflows depend on repo-level secrets that are unavailable in forks, so
they can never succeed. This is the standard approach used by large open-source projects (e.g.,
kubernetes, pytorch) to handle this.

Test plan

• Verify readthedocs.io returns 404 (confirmed via curl)
• Verify https://www.powermem.ai/docs returns 200 (confirmed via curl)
• Verify all ob-labs/* and openclaw/openclaw URLs are still valid (confirmed via

[Teingi]

LGTM