docs: correct contributor prerequisites and stale dev-env references (#1520)

The README prerequisites were both stale, and the docs restated the Go
version in three places.

## Prerequisites: name the source, do not restate the version

| README said | Reality |
|---|---|
| `Go 1.24.x` | `go 1.26` in
[go.mod](https://github.com/modelcontextprotocol/registry/blob/main/go.mod)
|
| `golangci-lint v2.4.0` | `v2.11.4` pinned in
[ci.yml:30](https://github.com/modelcontextprotocol/registry/blob/main/.github/workflows/ci.yml#L30)
|

Rather than swap in fresher numbers — which only resets the clock on the
same drift — this **removes the numbers** and names the authoritative
file:

```
- **Go** - version per the `go` directive in go.mod; the Go toolchain fetches it for you
- **golangci-lint** - version per the `golangci-lint-action` pin in ci.yml, so local lint matches CI
```

The Go version was stated in **three** places, which is exactly why all
three drifted together. All three now point at a single source, so the
prerequisites list cannot go stale.

Two notes on why the numbers earn so little in prose:

- **Go corrects itself.** `go.mod` has no `toolchain` directive, so
under the default `GOTOOLCHAIN=auto` the toolchain downloads the
required version automatically. A contributor on an older Go gets an
upgrade, not a failure — it only hard-errors under `GOTOOLCHAIN=local`.
(An earlier version of this description said such a contributor "cannot
build"; that was too strong.)
- **golangci-lint does not.** Version skew here genuinely changes what
you see: running CI's config under a newer golangci-lint (2.12.2)
surfaces 23 `goconst` findings in
`cmd/publisher/commands/validate_test.go` that CI's pinned 2.11.4 does
not report. That is why the README now points at the pin rather than a
number someone has to keep in sync.

## `make check` does more than documented

Documented in three files as "lint, unit tests and integration tests".
Actually [`check: dev-down lint validate
test-all`](https://github.com/modelcontextprotocol/registry/blob/main/Makefile#L85)
— it also runs schema validation and **stops your running `dev-compose`
environment**. Worth knowing before running it mid-session. The
Makefile's own `##` help string already said this correctly; only the
prose was stale.

## Other verified corrections

- **README project structure** omitted `cmd/registry/` — the server
entry point and ko/goreleaser build target — and `internal/importer/`.
- **`tests/integration/README.md`** said the suite launches **MongoDB**.
It launches PostgreSQL (`postgres-integration-test`), as the same file
admits nine lines later. It also cited `/v0/servers/{server_id}`, a path
removed a while ago; the test actually calls `GET /v0/servers` and `GET
/v0/servers/{serverName}/versions/latest`
([main.go:210,255](https://github.com/modelcontextprotocol/registry/blob/main/tests/integration/main.go#L210)).
- **`scripts/mirror_data/README.md`** pointed at
`internal/database/migrations/008_separate_official_metadata.sql`, which
does not exist — that migration is `009_`, while `008_` is
`clean_invalid_data.sql`. (Migration 008's own header still calls itself
"007a", which is how the numbering slipped.) Also swapped two "edit line
NN" pointers for identifier names, since both had already drifted
(`maxMigration` is at :30 not :24; the connection string at :23 not
:17), and corrected the fetch URL from `/v0.1/servers` to the
`/v0/servers` the script actually requests.
- **`.env.example`** was missing
`MCP_REGISTRY_ENABLE_REGISTRY_VALIDATION`, even though the config reads
it
([config.go:18](https://github.com/modelcontextprotocol/registry/blob/main/internal/config/config.go#L18))
and README:50 tells contributors to set it while pointing at
`.env.example` as *the* reference.
- **`docker-compose.yml`** set `MCP_REGISTRY_ENVIRONMENT`, which nothing
reads — no `ENVIRONMENT` env tag in `internal/config`, and no other
occurrence in the repo. Removed. (The Pulumi-side
`mcp-registry:environment` key is a separate, real thing and is
untouched.)
- **Deleted `CHANGES.md`** — 0 bytes, untouched since the squashed
history base, zero references anywhere.

## Verification

`docker compose config` validates. `grep` for `Go 1.x` / `golangci-lint
vX` across all `.md`/`.mdx` now returns nothing outside `complete.md`
(which #1522 deletes). Both `../../README.md#pre-requisites` links
resolve and the anchor matches the real `#### Pre-requisites` heading.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

---------

Co-authored-by: Claude Opus 5 <noreply@anthropic.com>

scripts/mirror_data/README.md

@@ -14,7 +14,7 @@ These scripts help you:
 
 ## Prerequisites
 
-- Go 1.24.x
+- Go — see the [prerequisites in the root README](../../README.md#pre-requisites) for the required version
 - PostgreSQL (via Docker or local installation)
 - Required Go packages:
   ```bash
@@ -31,7 +31,7 @@ go run scripts/mirror_data/fetch_production_data.go
 ```
 
 This will:
-- Fetch all servers from https://registry.modelcontextprotocol.io/v0.1/servers
+- Fetch all servers from https://registry.modelcontextprotocol.io/v0/servers
 - Handle pagination automatically
 - Save data to `scripts/mirror_data/production_servers.json`
 - Be respectful to the API with rate limiting
@@ -71,7 +71,7 @@ This will:
 4. Analyze the data and report statistics
 5. Show sample servers with NULL status values
 
-To test a different migration, edit `maxMigration` in the script (line 24)
+To test a different migration, edit `maxMigration` in `load_production_data.go`
 
 ### 4. Test Migrations
 
@@ -80,8 +80,8 @@ After loading the data, you can test migrations against real production data.
 #### Testing a Single Migration
 
 ```bash
-# Test migration 008
-cat internal/database/migrations/008_separate_official_metadata.sql | \
+# Test the separate_official_metadata migration
+cat internal/database/migrations/009_separate_official_metadata.sql | \
   docker exec -i test-postgres psql -U postgres -d registry_test
 ```
 
@@ -90,7 +90,7 @@ cat internal/database/migrations/008_separate_official_metadata.sql | \
 1. **Check the error output:**
 ```bash
 # Run migration and capture all output
-cat internal/database/migrations/008_separate_official_metadata.sql | \
+cat internal/database/migrations/009_separate_official_metadata.sql | \
   docker exec -i test-postgres psql -U postgres -d registry_test 2>&1 | \
   grep -E "(ERROR|NOTICE|WARNING)"
 ```
@@ -126,7 +126,7 @@ EOF
 # Start a transaction to test and rollback
 docker exec test-postgres psql -U postgres -d registry_test <<EOF
 BEGIN;
-\i /dev/stdin < internal/database/migrations/008_separate_official_metadata.sql
+\i /dev/stdin < internal/database/migrations/009_separate_official_metadata.sql
 -- Inspect the results
 \d servers
 SELECT COUNT(*) FROM servers;
@@ -145,7 +145,7 @@ go run scripts/mirror_data/load_production_data.go
 
 2. **Test your migration changes:**
 ```bash
-cat internal/database/migrations/008_separate_official_metadata.sql | \
+cat internal/database/migrations/009_separate_official_metadata.sql | \
   docker exec -i test-postgres psql -U postgres -d registry_test
 ```
 
@@ -183,7 +183,7 @@ The `load_production_data.go` script connects to:
 - User: `postgres`
 - Password: `testpass`
 
-Modify line 17 in the script if you need different connection parameters.
+Modify the `sql.Open` connection string in `load_production_data.go` if you need different connection parameters.
 
 ## Example Output
 
@@ -234,4 +234,4 @@ docker logs test-postgres
 ```
 
 ### Migration failures
-The script stops at migration 007 intentionally. To test migration 008, run it manually after the data is loaded.
+The script stops at migration 007 intentionally. To test later migrations (008 onwards), run them manually after the data is loaded, in order.