feat: add ticket-to-PR provider matrix

[all-hands-bot]

Summary

• add Jira to GitLab and Jira to Bitbucket recommended automations
• add Linear to GitHub, Linear to GitLab, and Linear to Bitbucket recommended automations
• add a shared setup skill with dependency and backlog safeguards
• register GitLab in the integration catalog

Closes #437
Closes #438
Closes #439
Closes #440
Closes #441
Related to #422

Validation

• npm run build
• python3 scripts/sync_extensions.py --check
• git diff --check
• pytest: 529 passed, 6 skipped; two unrelated local package-version failures

This PR was created by an AI agent (OpenHands) on behalf of the user.

[all-hands-bot]

👋 This PR needs a couple of things fixed before OpenHands can review it:

• the PR description's HUMAN: section needs at least 20 characters describing what you tested, not just the template placeholder

Push an update once this is addressed and this check re-runs automatically.

This is an automated check - no AI was used to generate this comment.

[all-hands-bot]

👋 This PR needs a couple of things fixed before OpenHands can review it:

• the PR description's HUMAN: section needs at least 20 characters describing what you tested, not just the template placeholder

Push an update once this is addressed and this check re-runs automatically.

This is an automated check - no AI was used to generate this comment.

[all-hands-bot]

👋 This PR needs a couple of things fixed before OpenHands can review it:

• the PR description's HUMAN: section needs at least 20 characters describing what you tested, not just the template placeholder

Push an update once this is addressed and this check re-runs automatically.

This is an automated check - no AI was used to generate this comment.