feat: add Zendesk client and update documentation

Integrate Zendesk API client into ES.FX, updating related documentation for new features. Includes client authentication details, configuration options, and integration notes.

Author: winromulus

CLAUDE.md

@@ -11,8 +11,9 @@ Markdown. Use it as the source of truth for architecture and usage instead of du
 - **Patterns & contributor rules** (Result/Problem, primitives, hosting, conventions, testing, *creating a
   library*) → [`docs/development/`](docs/development/index.md)
 - **Additions** (one-per-dependency helpers) → [`docs/additions/`](docs/additions/index.md)
-- **Ignite & Sparks** (the bootstrap, per-Spark reference, *creating a Spark*) → [`docs/ignite/`](docs/ignite/index.md)
-- **Feature libraries** (Transactional Outbox, Migrations) → [`docs/libraries/`](docs/libraries/index.md)
+- **Ignite & Sparks** (the bootstrap, configuration model, per-Spark reference, *creating a Spark*) →
+  [`docs/ignite/`](docs/ignite/index.md)
+- **Feature libraries** (Transactional Outbox, Migrations, Zendesk API client) → [`docs/libraries/`](docs/libraries/index.md)
 
 > **Keep the docs in sync.** `docs/` is a first-class deliverable, not an afterthought. When you add,
 > change, or remove a public API, package, Spark, or convention, update the matching `docs/` page **in the
@@ -22,12 +23,13 @@ Markdown. Use it as the source of truth for architecture and usage instead of du
 ## Project Overview
 
 ES.FX (EmberStack Framework) is a collection of reusable .NET extensions and application frameworks published
-as NuGet packages under the `ES.FX.*` namespace. Every project in `src/` builds a package; `tests/` and
-`playground/` are not published. The flagship is **Ignite**, an opinionated, "just add water" application
-bootstrap (OpenTelemetry, health checks, resilience, service integrations).
+as NuGet packages under the `ES.FX.*` namespace. The flagship is **Ignite**, an opinionated, "just add water"
+application bootstrap (OpenTelemetry, health checks, resilience, service integrations).
 
-All library projects target **.NET 10** (`net10.0`). Some stale `bin/obj` output may still reference
-`net9.0` — trust the `.csproj`, not build artifacts.
+All library projects target **.NET 10** (`net10.0`). Nearly every project in `src/` builds a NuGet package;
+the exception is `ES.FX.Zendesk.MCP.Host`, a deployable ASP.NET Core MCP-server host (Docker-targeted) that
+opts out with `GeneratePackageOnBuild=false` / `IsPackable=false`. `tests/` and `playground/` are never
+published.
 
 ## Commands
 
@@ -70,23 +72,30 @@ Five independently consumable layers; dependencies point downward only:
    handling, and graceful shutdown. → [`docs/development/hosting.md`](docs/development/hosting.md)
 4. **ES.FX.Ignite** (+ `ES.FX.Ignite.Spark` base + the `ES.FX.Ignite.{Provider}` **Sparks**) — the
    opinionated bootstrap. → [`docs/ignite/`](docs/ignite/index.md)
-5. **Feature libraries** — Transactional Outbox and Migrations, usable without Ignite. →
-   [`docs/libraries/`](docs/libraries/index.md)
+5. **Feature libraries** — Transactional Outbox, Migrations, and the Zendesk API client, usable without
+   Ignite. → [`docs/libraries/`](docs/libraries/index.md)
 
 Ignite activates in **two phases**: `builder.Ignite(...)` on `IHostApplicationBuilder` (pre-build), then
 `app.Ignite()` on `IHost` (post-build). A **Spark** plugs a service into Ignite (config binding, DI
 registration, health checks, OpenTelemetry) and follows a fixed shape — study
 `src/ES.FX.Ignite.StackExchange.Redis/` as the canonical example. Full model and per-Spark reference:
 [`docs/ignite/`](docs/ignite/index.md) and [`docs/ignite/creating-a-spark.md`](docs/ignite/creating-a-spark.md).
 
+A newer Zendesk vertical spans the layers: `ES.FX.Zendesk` (typed Zendesk API client,
+[`docs/libraries/zendesk-client.md`](docs/libraries/zendesk-client.md)), `ES.FX.Ignite.Zendesk` (its Spark,
+[`docs/ignite/sparks/zendesk.md`](docs/ignite/sparks/zendesk.md)), and `ES.FX.Zendesk.MCP.Host` (the
+deployable MCP server app noted above; its MCP wiring is host-inline — there is no MCP Spark package).
+
 ## Conventions & Build Configuration
 
 Global settings live in `Directory.Build.props` and apply to every project:
 - **Warnings are errors** (`TreatWarningsAsErrors=true`), nullable + implicit usings enabled, XML docs
   generated, debug symbols embedded.
 - `ES.FX.*` non-test projects **auto-pack on build** (`GeneratePackageOnBuild=true`) into `.artifacts/nuget`;
   they embed `README.md` and `package.icon.png`, MIT-licensed, `JetBrains.Annotations` referenced privately.
-- Test projects (`*.Tests`) are excluded from packing and from code coverage, and emit per-project TRX loggers.
+  Host apps opt out by setting `GeneratePackageOnBuild=false` in their `.csproj`.
+- Test projects (name contains `.Tests`, including `.Tests.SUT`) are excluded from packing and from code
+  coverage, and emit per-project TRX loggers.
 - **Central Package Management**: all versions are pinned in `Directory.Packages.props`
   (`ManagePackageVersionsCentrally=true`). Add/bump versions there, never inline in a `.csproj`.
 
@@ -102,15 +111,22 @@ Naming:
 
 - **xUnit v3** (`xunit.v3`), Moq, coverlet for coverage.
 - Functional tests use **Testcontainers** and require a running Docker engine: MsSql, Redis, PostgreSQL,
-  MariaDB. Shared fixtures live in `tests/ES.FX.Shared.{Db}.Tests`.
+  MariaDB. Shared fixtures live in `tests/ES.FX.Shared.{Service}.Tests`.
 - `.SUT` projects are real hosts (ASP.NET etc.) started via `Microsoft.AspNetCore.Mvc.Testing` for
   end-to-end coverage of a Spark. Details: [`docs/development/testing.md`](docs/development/testing.md).
 
 ## CI/CD
 
-`.github/workflows/pipeline.yaml` (single pipeline, all branches):
-- Installs .NET `10.x` and **GitVersion 6.x**; `dorny/paths-filter` skips build when only non-source paths change.
-- Versioning via `GitVersion.yaml` (`ContinuousDelivery` mode, commit-message bumps like `+semver: minor`, tag prefix `v`).
-- `main` builds `Release` and **publishes to GitHub Packages + NuGet.org** and cuts a GitHub release; other
-  branches build `Debug` and don't publish. Dependabot PRs don't push packages.
-- Dependency bumps are grouped via `.github/dependabot.auto.yaml`; stale issues handled by `stale.yaml`.
+`.github/workflows/pipeline.yaml` (single pipeline, all branches, per-branch concurrency cancel):
+- Installs .NET `10.x` and **GitVersion 6.x**; `dorny/paths-filter` skips the build when only non-source
+  paths change (docs-only changes don't build).
+- Versioning via `GitVersion.yaml`: tag prefix `v`, commit-message bumps (`+semver: major|minor|patch`);
+  `main` defaults to a **patch** increment per merge, other branches produce prerelease versions labeled by
+  branch.
+- `main` builds `Release`; all other branches build `Debug`.
+- **Publishing**: any direct branch push (not PRs, not Dependabot) that touches source pushes the built
+  packages to **GitHub Packages** — so pushing a feature branch publishes prerelease packages. `main`
+  additionally publishes to **NuGet.org** and cuts a GitHub release (`v{semver}`).
+- Dependabot: `.github/dependabot.yaml` groups all NuGet + GitHub Actions bumps into one daily batch;
+  `.github/workflows/dependabot.auto.yaml` auto-approves and squash-auto-merges Dependabot PRs once checks
+  pass. Stale issues are handled by `stale.yaml`.

docs/ignite/sparks/index.md

@@ -90,14 +90,19 @@ Every Spark, grouped by function.
 | [Azure Blob Storage](./azure-storage-blobs.md) | Registers a `BlobServiceClient` for Azure Blob Storage. |
 | [Azure Queue Storage](./azure-storage-queues.md) | Registers a `QueueServiceClient` for Azure Queue Storage. |
 
+### External services
+
+| Spark | Purpose |
+| --- | --- |
+| [Zendesk](./zendesk.md) | Registers the [ES.FX.Zendesk](../../libraries/zendesk-client.md) typed `IZendeskClient` (OAuth `client_credentials`) with a live health check and tracing. |
+
 ### API & documentation
 
 | Spark | Purpose |
 | --- | --- |
 | [API versioning](./asp-versioning.md) | Wires `Asp.Versioning` into Ignite for versioned API endpoints. |
 | [NSwag](./nswag.md) | Generates OpenAPI documents and UI via NSwag (adds a post-build `app.IgniteNSwag()` step). |
 | [Swashbuckle](./swashbuckle.md) | Generates OpenAPI documents and Swagger UI via Swashbuckle. |
-| [Model Context Protocol](./model-context-protocol.md) | Hosts a Model Context Protocol (MCP) server, based on the `ModelContextProtocol.AspNetCore` SDK. |
 
 ### Observability