test(11.1-06): plant one fixture per docs checker rule and run them in the gate

- testdata/clean passes every check; 63 violation cases each overlay one
  fault and a want.txt naming the single problem it must produce
- TestPlantedViolations also plants the forbidden name (split literals)
  and symlink escapes at run time; TestBuildOutputGuard covers --out
- check-phase11.1.sh --self-test runs the corpus through a go test -json
  detector that refuses FAIL, SKIP, zero tests and no tests to run
- the self-test scratch copy now carries examples/ and README.md, so its
  baseline sees the example command literals the real tree sees

internal/docsite/testdata/clean/README.md

@@ -0,0 +1,3 @@
+# Docs fixture
+
+The clean fixture for the docs checkers. `demo.Hello` is checked here too.

internal/docsite/testdata/clean/config/app.yaml

@@ -0,0 +1,6 @@
+app:
+  # docs:start db
+  db:
+    host: localhost
+    port: 5432
+  # docs:end db

internal/docsite/testdata/clean/docs/extras/faq.md

@@ -0,0 +1,15 @@
+---
+title: FAQ
+description: "Questions about the demo."
+section: extras
+order: 20
+---
+# FAQ
+
+## Does it migrate
+
+Yes, run `./bin/demo migrate`, then `summer docs:sync` after a source change.
+
+```text
+summer not:checked in a text fence
+```

internal/docsite/testdata/clean/docs/extras/usage.md

@@ -0,0 +1,18 @@
+---
+title: Usage
+description: "Build a greeter and call it."
+section: extras
+order: 10
+---
+# Usage
+
+## Call it
+
+A `demo.Greeter` greets by name:
+
+```go src=modules/demo/demo_test.go#greet
+g := Greeter{Name: "blog"}
+got := g.Greet()
+```
+
+See [Greet someone](../guide/start.md#greet-someone).

internal/docsite/testdata/clean/docs/guide/config.md

@@ -0,0 +1,20 @@
+---
+title: Config
+description: "Configure the demo database."
+section: guide
+order: 20
+---
+# Config
+
+The database block of `config/app.yaml`:
+
+```yaml src=config/app.yaml#db
+db:
+  host: localhost
+  port: 5432
+```
+
+## Settings
+
+> [!WARNING]
+> Keep the port in step with the database server.

internal/docsite/testdata/clean/docs/guide/start.md

@@ -0,0 +1,32 @@
+---
+title: Start
+description: "Install the demo and greet someone."
+section: guide
+order: 10
+---
+# Start
+
+The demo module greets people.
+
+## Install
+
+Build the docs with `summer docs:build`, or run the application:
+
+```sh
+$ summer docs:build --out site
+./bin/demo serve --addr 127.0.0.1:8080
+```
+
+## Greet someone
+
+Call `demo.Hello`:
+
+```go src=modules/demo/example_test.go#ExampleHello
+fmt.Println(demo.Hello("blog"))
+// Output: Hello, blog
+```
+
+> [!TIP]
+> The [demo reference](../../modules/demo/README.md#usage) lists the whole API.
+
+Continue with [configuration](config.md) or jump back to [install](#install).

internal/docsite/testdata/clean/docs/index.md

@@ -0,0 +1,12 @@
+---
+title: Demo docs
+description: "The landing page of the clean fixture."
+section: index
+order: 0
+---
+# Demo docs
+
+Start with the [start guide](guide/start.md), then read [usage](extras/usage.md#call-it).
+
+> [!NOTE]
+> Every page of this fixture passes every check.

internal/docsite/testdata/clean/docs/site.yaml

@@ -0,0 +1,14 @@
+title: Demo
+description: "Demo is the clean docs checker fixture."
+base_url: ""
+edit_url: "https://forge.example/edit/{path}"
+source_url: "https://forge.example/src/{path}"
+llms_notes:
+  - "Every page of this fixture passes every check."
+sections:
+  - name: guide
+    title: Guide
+  - name: extras
+    title: Extras
+  - name: api
+    title: API reference

internal/docsite/testdata/clean/go.mod

@@ -0,0 +1,3 @@
+module example.com/docfixture
+
+go 1.27.0

internal/docsite/testdata/clean/modules/demo/README.md

@@ -0,0 +1,19 @@
+# demo
+
+Demo greets people by name.
+
+```go
+import "example.com/docfixture/modules/demo"
+```
+
+## Usage
+
+Call `demo.Hello` or build a `demo.Greeter` and call `demo.Greeter.Greet`.
+
+See the [start guide](../../docs/guide/start.md#install).
+
+## Testing
+
+```sh
+go test ./modules/demo
+```

internal/docsite/testdata/clean/modules/demo/demo.go

@@ -0,0 +1,17 @@
+// Package demo is the docs checker fixture module.
+package demo
+
+// Hello returns a greeting for name.
+func Hello(name string) string {
+	return "Hello, " + name
+}
+
+// Greeter greets by name.
+type Greeter struct {
+	Name string
+}
+
+// Greet returns the greeting for the greeter's name.
+func (g Greeter) Greet() string {
+	return Hello(g.Name)
+}

internal/docsite/testdata/clean/modules/demo/demo_test.go

@@ -0,0 +1,13 @@
+package demo
+
+import "testing"
+
+func TestGreet(t *testing.T) {
+	// docs:start greet
+	g := Greeter{Name: "blog"}
+	got := g.Greet()
+	// docs:end greet
+	if got != "Hello, blog" {
+		t.Fatalf("Greet() = %q", got)
+	}
+}

internal/docsite/testdata/clean/modules/demo/example_test.go

@@ -0,0 +1,12 @@
+package demo_test
+
+import (
+	"fmt"
+
+	"example.com/docfixture/modules/demo"
+)
+
+func ExampleHello() {
+	fmt.Println(demo.Hello("blog"))
+	// Output: Hello, blog
+}