GitHub CI workflows

[tgrunnagle]

Add GitHub Actions CI Pipeline

Summary

This PR implements a comprehensive GitHub Actions CI pipeline that runs on every pull request to ensure code quality and catch issues early.

• Adds modular, reusable workflows for lint, test, and integration stages
• Entry point workflow (ci.yml) orchestrates all checks with proper dependencies
• Integration tests only run after lint and unit tests pass
• Adds new format:check tasks to Taskfile.yml for CI-compatible format validation

Closes: #92

Changes

Workflow Files (.github/workflows/)

File	Purpose
ci.yml	Entry point - triggers on PR events, calls other workflows
lint.yml	Linting, format checking, and type checking for bot2 (Python) and backend (Go)
test.yml	Unit tests for bot2 and backend
integration.yml	Integration tests using Docker Compose

Taskfile.yml

Added two new tasks for CI-compatible format checking (non-modifying):

• bot2:format:check - Runs ruff format --check for Python code
• be:format:check - Runs gofmt -l check for Go code

Workflow Architecture

ci.yml (entry point)
  ├── lint.yml (parallel)
  │     ├── bot2-lint: lint, format check, typecheck
  │     └── backend-lint: lint, format check, vet
  ├── test.yml (parallel)
  │     ├── bot2-test: unit tests
  │     └── backend-test: unit tests
  └── integration.yml (after lint + test pass)
        └── integration: docker compose + integration tests

Key Features

• Modular design: Each workflow is reusable via workflow_call
• Parallel execution: Lint and test jobs run in parallel for faster feedback
• Gated integration tests: Only run after lint and unit tests pass
• Health check polling: Integration workflow waits for services to be ready before running tests
• Cleanup on failure: Docker Compose cleanup runs even if tests fail

Test Plan

• Verify task bot2:format:check works locally
• Verify task be:format:check works locally
• Create PR and verify all workflow jobs trigger
• Verify lint job catches intentional formatting issues
• Verify integration tests run after lint and test jobs complete