Set up GitHub Actions CI/CD pipeline for analytics microservice

Description

Create a CI/CD pipeline using GitHub Actions for the analytics microservice. The pipeline must validate code quality and ensure safe deployments through a staged flow that prevents broken or insecure code from reaching production.

Pipeline stages:

• Build verification
• Static analysis / bad-practice detection
• Test execution (unit + integration)
• Basic security checks
• Artifact generation
• Staged deployment flow (dev → staging → production gate)

Improvement plan: https://docs.google.com/document/d/1hVfIurPqAJJ1PN1EalmvrWXnGNt5sY21MI-409lrXpU/edit?tab=t.klqavlz4cis7#heading=h.8vek9yxw

Parent epic: #35048

Acceptance Criteria

• GitHub Actions workflow file created for the analytics microservice
• Build verification step: fails fast on compilation errors
• Static analysis / bad-practice detection (e.g. Checkstyle, SpotBugs, or equivalent)
• Test execution: unit tests and integration tests (Testcontainers) run on every PR
• Basic security checks (e.g. dependency vulnerability scan via OWASP or similar)
• Artifact generation: Docker image or JAR produced on successful build
• Staged deployment flow: broken or insecure builds cannot reach production
• Pipeline runs on PR open/update and on merge to main

Additional Context

• Source task: Task 27 (Set up a Baseline CI/CD Pipeline with GitHub Actions) from the improvement plan
• Blocked by: #35050 (ingest code refactor), #35053 (unit tests), #35054 (integration tests)
• Related branch: issue-34849-Add-dotCMS-Analytics-Proxy-Endpoint-for-/v1/analytics/-to-dot-ca-event-manager

No workflow file or test path is named. Start with the improvement plan and parent epic #35048, then inspect the analytics microservice and blocked issues #35050, #35053, and #35054. Done means a GitHub Actions workflow runs build, analysis, tests, security checks, artifact generation, and gated dev-to-production deployment on pull requests and merges to main.