feat(suite): Implement Suites

[TwiN]

Summary

This is a new core feature, and makes massive changes throughout the entire codebase.

Suites are collections of endpoints that are executed sequentially with a shared context.

This allows you to create complex monitoring scenarios where the result from one endpoint can be used in subsequent endpoints, enabling workflow-style monitoring.

Here are a few cases in which suites could be useful:

• Testing multi-step authentication flows (login -> access protected resource -> logout)
• API workflows where you need to chain requests (create resource -> update -> verify -> delete)
• Monitoring business processes that span multiple services
• Validating data consistency across multiple endpoints

This is a feature I have been wanting to implement for a very long time, and coupled with Gatus' extremely powerful and customizable endpoint health validating capabilities (vs. most other status pages that are limited to basic checks), I believe that suites are what will bring Gatus into a league of its own.

Fixes #1230

Fixes #1233 (unrelated to suites)

Fixes #1214 (this deprecates disable-monitoring-lock in favor of a new concurrency parameter): this was needed, because some complex suites could take minutes to complete, which would have locked concurrent runs for as much time (not acceptable)

Checklist

• Tested and/or added tests to validate that the changes work as intended, if applicable.
• Updated documentation in README.md, if applicable.

[Copilot]

Pull Request Overview

This PR implements Suites - a major new feature that allows creating collections of endpoints that execute sequentially with shared context. This enables complex monitoring scenarios like multi-step authentication flows and API workflows where results from one endpoint can be used in subsequent endpoints.

Key changes include:

• Added complete suite execution engine with context sharing and sequential endpoint processing
• Added suite storage layer with database schema and API endpoints
• Added comprehensive frontend UI for viewing suite execution results and flow diagrams

Reviewed Changes

Copilot reviewed 70 out of 74 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
web/static/css/app.css	Updated compiled Tailwind CSS with new suite-related styles
web/app/src/views/SuiteDetails.vue	New comprehensive suite details view with execution flow visualization
web/app/src/views/Home.vue	Enhanced dashboard to display both endpoints and suites
web/app/src/views/EndpointDetails.vue	Migrated from helper mixin to time utilities
web/app/src/utils/time.js	New centralized time formatting utilities
web/app/src/utils/format.js	New duration formatting utilities
web/app/src/router/index.js	Added route for suite details page
web/app/src/components/*	New suite-specific UI components for flow visualization
storage/store/sql/sql.go	Added comprehensive suite storage with database schema
config/suite/*	Core suite implementation with execution engine
watchdog/*	Extended monitoring system to support suite execution
metrics/metrics.go	Added Prometheus metrics for suite monitoring

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[TwiN]

I've gone over the changes at least 20 times. I'm sure I missed something, so I'll have to let this soak on the latest tag for some time, but here goes nothing.