[StevenTCramer]

Summary

Generator fix: source/timewarp-nuru-analyzers/generators/interpreter/dsl-interpreter.expressions.cs
(semantic CreateBuilder gate, Design region added). Regression test:
tests/timewarp-nuru-mcphost-tests/mcphost-07-host-builder-chain.cs (stand-in WebApplication
with a static CreateBuilder, real AddMcpServer() + WithNuruTools, same method as the Nuru
app). Without the fix the file fails to compile with
NURU_S999: Unrecognized DSL method: AddMcpServer (checked by reverting the fix); with it, 2/2 pass.
mcp-hosting.md is unchanged because its snippet is the supported usage.

Probe (tw-nuru-verify style): fresh Microsoft.NET.Sdk.Web project in /tmp, empty
NUGET_PACKAGES, TimeWarp.Nuru.McpHost 4.0.0-beta.13 packed by ./bin/dev build (source-mapped
to artifacts/packages), ModelContextProtocol.AspNetCore 2.4.0, Program.cs = the doc's L50
snippet. dotnet build: Build succeeded, 0 errors. dotnet run -- --check: probe-ok.

Gates

Gate	Command	Result
Build	./bin/dev build	Pass: Build completed successfully, 0 warnings, 0 errors
Test	ganda runfile cache --clear then ./bin/dev test	Pass: exit 0; CI multi-mode 2197 total, 2191 passed, 6 skipped, 0 failed; standalone 0 failed
Audit	ganda repo audit	Pass: "Repository passes all audit checks." (first run passed with 1 advisory, vscode-window-icon: .vscode/settings.json missing; ganda repo audit --fix wrote the git-ignored local file, rerun clean)

Test plan

Smoke:

ganda runfile cache --clear
dotnet run tests/timewarp-nuru-mcphost-tests/mcphost-07-host-builder-chain.cs

Expect: both McpHostHostBuilderChain tests pass (tools hbc-ping and hbc-greet registered;
the Nuru app beside the host builder still dispatches). Reverting the one-line "CreateBuilder" when IsNuruAppCreateBuilder(...) guard makes the file fail to build with
NURU_S999: Unrecognized DSL method: AddMcpServer.

Kanban task 531
Session: 7dce871f-a50c-41b9-b2b5-aefa4c4ad890