Big docs tidy up in preparation for launch (#364)

## Motivation and Context
Docs currently don't have very clear organisation, and don't explain
core flows.

This fixes #89 (although we still might want to push these to
`https://modelcontextprotocol.io/docs/`), based on the plan there.

One minor change from that plan is that I merged tutorials and guides,
because they ended up basically being duplicates which I thought would
be annoying for us to keep in sync. Additionally in the Diátaxis
framework, tutorials and guides are separated by whether they are
focused on acquisition of skills (e.g. in a learning environment) or
application of skills (e.g. in a work environment). I expect the
registry to be something that will be used occasionally in a work
environment, rather than a fundamental 'learnable' skill so I think it's
reasonable not to have tutorials and fold these into guides.

## How Has This Been Tested?
- Read through all these updated docs
- Unit and integration tests (that previously used examples.md and use
the schema) working
- Ran `npx markdown-link-check .` to check all the links work

## Breaking Changes
Links to old docs will break, but I don't think there are any. All
internal links have been checked and updated.

## Types of changes
<!-- What types of changes does your code introduce? Put an `x` in all
the boxes that apply: -->
- [ ] Bug fix (non-breaking change which fixes an issue)
- [ ] New feature (non-breaking change which adds functionality)
- [ ] Breaking change (fix or feature that would cause existing
functionality to change)
- [x] Documentation update

README.md

@@ -1,30 +1,14 @@
 # MCP Registry
 
+The MCP registry provides MCP clients with a list of MCP servers, like an app store for MCP servers.
+
+📖 **[Full documentation](./docs)**
+
+## Development Status
+
 > [!WARNING]  
 > The registry is under [active development](#development-status). The registry API spec is unstable and the official MCP registry database may be wiped at any time.
 
-📖 **[API Documentation](https://staging.registry.modelcontextprotocol.io/docs)** | 📚 **[Technical Docs](./docs)**
-
-## What is the registry?
-
-The registry will provide MCP clients with a list of MCP servers, like an app store for MCP servers. (In the future it might do more, like also hosting a list of clients).
-
-There are two parts to the registry project:
-1. 🟦 **The MCP registry spec**: An [API specification](./docs/server-registry-api/) that allows anyone to implement a registry.
-2. 🟥 **The Official MCP registry**: A hosted registry following the MCP registry spec at [`registry.modelcontextprotocol.io`](https://registry.modelcontextprotocol.io). This serves as the **authoritative repository** for publicly-available MCP servers. Server creators publish once, and all consumers (MCP clients, aggregators, marketplaces) reference the same canonical data. This is owned by the MCP open-source community, backed by major trusted contributors to the MCP ecosystem such as Anthropic, GitHub, PulseMCP and Microsoft.
-
-The registry is built around the [`server.json`](./docs/server-json/) format - a standardized way to describe MCP servers that works across discovery, initialization, and packaging scenarios.
-
-In time, we expect the ecosystem to look a bit like this:
-
-![](./docs/ecosystem-diagram.excalidraw.svg)
-
-Note that MCP registries are _metaregistries_. They host metadata about packages, but not the package code or binaries. Instead, they reference other package registries (like NPM, PyPi or Docker) for this.
-
-Additionally, we expect clients pull from _subregistries_. These subregistries add value to the registry ecosystem by providing curation, or extending it with additional metadata. The Official MCP registry expects a lot of API requests from ETL jobs from these subregistries.
-
-## Development Status
-
 **2025-09-04 update**: We're targeting a 'preview' go-live on 8th September. This may still be unstable and not provide durability guarantees, but is a step towards being more solidified. A general availability (GA) release will follow later.
 
 Current key maintainers:
@@ -106,7 +90,7 @@ make publisher
 ./cmd/publisher/bin/mcp-publisher --help
 ```
 
-See [the publisher README](./cmd/publisher/README.md) for more details.
+See [the publisher guide](./docs/guides/publishing/publish-server.md) for more details.
 
 #### Other commands
 
@@ -130,9 +114,7 @@ For Claude and other AI tools: Always prefer make targets over custom commands w
 │   └── publisher/           # Server publishing tool
 ├── data/                    # Seed data
 ├── deploy/                  # Deployment configuration (Pulumi)
-├── docs/                    # Technical documentation
-│   ├── server-json/         # server.json specification & examples
-│   └── server-registry-api/ # API specification
+├── docs/                    # Documentation
 ├── internal/                # Private application code
 │   ├── api/                 # HTTP handlers and routing
 │   ├── auth/                # Authentication (GitHub OAuth, JWT, namespace blocking)
@@ -165,4 +147,4 @@ The registry validates namespace ownership when publishing. E.g. to publish...:
 
 ## More documentation
 
-See the [docs](./docs) folder for more details if your question has not been answered here!
+See the [documentation](./docs) for more details if your question has not been answered here!