feat(autofix): Add GitLab repository support

[dnplkndll]

Summary

• Add GitLab as a supported repository provider for Autofix, enabling Merge Request creation for GitLab repositories alongside existing GitHub PR support
• Create BaseRepoClient abstract base class defining the common interface for all repository providers
• Implement GitLabRepoClient using the python-gitlab library with full MR creation capability
• Add common return types (BranchRefResult, PullRequestResult) ensuring type consistency across providers
• Add GitHub Actions workflow to build and push Docker images to GCP Artifact Registry
• Add CodeRabbit configuration for automated code reviews

Changes

New Files

• src/seer/automation/codebase/base_repo_client.py - Abstract base class with common interface
• src/seer/automation/codebase/gitlab_repo_client.py - GitLab provider implementation
• tests/automation/codebase/test_gitlab_repo_client.py - Comprehensive unit tests (40+ test cases)
• .github/workflows/build-push-gcp.yml - CI workflow for GCP Artifact Registry
• .coderabbit.yaml - CodeRabbit AI review configuration

Modified Files

• src/seer/automation/codebase/repo_client.py - Refactored to GitHubRepoClient, inherits from base, adds factory function
• src/seer/automation/autofix/autofix_context.py - Updated to use BaseRepoClient return type
• src/seer/configuration.py - Added GITLAB_TOKEN and GITLAB_INSTANCE_URL config
• src/seer/automation/codebase/models.py - Added GitLabMrReviewComment TypedDict
• requirements-constraints.txt / requirements.txt - Added python-gitlab>=4.0.0

Architecture

                    BaseRepoClient (ABC)
                           |
          +----------------+----------------+
          |                                 |
    GitHubRepoClient                 GitLabRepoClient
    (refactored)                    (new)

CI/CD

New workflow builds AMD64 Docker images and pushes to:
us-central1-docker.pkg.dev/kencove-prod/kencove-docker-repo/seer

Triggers on:

• Push to main
• Merged PRs
• Manual dispatch

Test plan

• Run mypy type checking: make mypy
• Run GitLab client unit tests: pytest tests/automation/codebase/test_gitlab_repo_client.py -v
• Verify existing GitHub tests still pass: pytest tests/automation/codebase/test_repo_client.py -v
• Verify Docker image builds and pushes to GCP after merge

🤖 Generated with Claude Code

Summary by CodeRabbit

• New Features

  • GitLab support with a provider-agnostic repo client, Langfuse 3.x compatibility and context, and a new project AI configuration.

• Bug Fixes / Improvements

  • More resilient CI and model-fetch flows with graceful fallbacks, multi-tag image publishing, longer build timeout, and faster dependency installs.

• Chores

  • Large dependency upgrades, workflow/tooling refinements, and linting/Makefile improvements.

• Tests

  • Expanded and updated test coverage for GitLab integration, model changes, and related workflows.

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