Clarify Repl.Mcp sample setup for agent hosts

[autocarl]

Summary

• Clarifies that Repl.Mcp is the component used to build MCP servers, not the server users install directly.
• Expands sample 08 into a copy/paste-ready MCP server sample with CLI, REPL, MCP, MCP Inspector, Cursor, VS Code, Claude Code, Cline, and generic MCP client guidance.
• Updates host guidance from fragile dotnet run --project ... launches to an initial build plus dotnet run --no-build --project ... -- mcp serve, with Windows path/quoting notes.
• Keeps reusable host config JSON under samples/08-mcp-server/configs/, using a shared mcpServers shape for generic/Cursor/Cline/Claude-style clients and a separate VS Code servers shape.
• Shows Windows JSON paths with doubled source backslashes so copied examples remain valid JSON.

Closes #35.

Verification

• python3 -m json.tool samples/08-mcp-server/configs/generic-mcp-client.json — passed
• python3 -m json.tool samples/08-mcp-server/configs/vscode.mcp.json — passed
• git diff --check — passed
• npx --yes markdownlint-cli2 '**/*.md' — passed, 0 errors
• Windows path source backslash-count check — passed (14 backslash characters for full JSON path examples)
• dotnet restore src/Repl.slnx --force — passed
• dotnet build src/Repl.slnx -c Release -warnaserror --no-restore — passed, 0 warnings/errors
• dotnet build samples/08-mcp-server/McpServerSample.csproj -c Release -warnaserror — passed, 0 warnings/errors
• dotnet test --solution src/Repl.slnx -c Release --no-build --no-restore — passed, 989 succeeded / 1 skipped / 0 failed
• dotnet run --no-build --project samples/08-mcp-server/McpServerSample.csproj -- contacts --json — returned valid JSON
• MCP no-build startup smoke — emitted 0 bytes before client input
• GitHub Actions on 4b6209a — passed: Lint Documentation, Build and Test (ubuntu-latest), Build and Test (macos-latest), Build/Test/Pack, Shell Completion Smoke; GitHub Release skipped

[autocarl]

Addressed the host-configuration review in eca93ed.

Per-point response:

1. Claude Desktop macOS path — fixed to ~/Library/Application Support/Claude/claude_desktop_config.json in both docs/mcp-reference.md and the sample README.
2. Fragile dotnet run --project host configs — host-facing sample configs now use an initial build step plus dotnet run --no-build --project ... -- mcp serve; docs also recommend a published executable/dotnet tool for shared configs.
3. Windows quoting/path guidance — added explicit Windows JSON examples with doubled backslashes and documented that Windows users should prefer .vscode/mcp.json over inline code.cmd --add-mcp JSON.
4. Claude Code provisioning — clarified claude mcp add as the standard flow and documented .mcp.json plus ~/.claude.json for file-based provisioning.
5. Broken result-flow anchor — changed the removed #demo-workflow link to #test-with-mcp-inspector.
6. Cline guidance — replaced the marketplace wording with Configure MCP Servers / cline_mcp_settings.json and clarified that the marketplace will not install this local sample.
7. Program.cs header — updated the sample comment to use an absolute project path and --no-build.
8. Duplicated config blob — removed the byte-identical Cursor config file and points Cursor at the shared mcpServers JSON shape; VS Code keeps its separate servers shape.

Also restored the CLI continuation example with --result:cursor=5 and aligned the root README sample title.

Verification run locally:

• npx --yes markdownlint-cli2 '**/*.md' — passed, 0 errors
• dotnet restore src/Repl.slnx --force — passed
• dotnet build src/Repl.slnx -c Release -warnaserror --no-restore — passed, 0 warnings/errors
• dotnet build samples/08-mcp-server/McpServerSample.csproj -c Release -warnaserror — passed, 0 warnings/errors
• dotnet test --solution src/Repl.slnx -c Release --no-build --no-restore — passed, 978/978
• sample smoke: dotnet run --no-build --project samples/08-mcp-server/McpServerSample.csproj -- contacts --json — returned valid JSON
• MCP no-build startup smoke — emitted 0 bytes before client input

I did not find existing GitHub inline review comments or issue comments on this PR to reply to individually, so I am posting this as the review-round response.

[carldebilly]

@codex please review this pr

[chatgpt-codex-connector]

💡 Codex Review

Here are some automated review suggestions for this pull request.

Reviewed commit: eca93ed653

ℹ️ About Codex in GitHub

Your team has set up Codex to review pull requests in this repo. Reviews are triggered when you

• Open a pull request for review
• Mark a draft as ready
• Comment "@codex review".

If Codex has suggestions, it will comment; otherwise it will react with 👍.

Codex can also answer questions or update the PR. Try commenting "@codex address that feedback".

[autocarl]

Rebased the PR branch onto current main and resolved the docs/mcp-reference.md conflict by keeping both the new Inspector CLI smoke guidance from main and this PR's dotnet run --no-build sample guidance.

Head is now c6a3c63; GitHub reports the PR as mergeable and all checks are green.

[chatgpt-codex-connector]

💡 Codex Review

Here are some automated review suggestions for this pull request.

Reviewed commit: c6a3c63acc

ℹ️ About Codex in GitHub

Your team has set up Codex to review pull requests in this repo. Reviews are triggered when you

• Open a pull request for review
• Mark a draft as ready
• Comment "@codex review".

If Codex has suggestions, it will comment; otherwise it will react with 👍.

Codex can also answer questions or update the PR. Try commenting "@codex address that feedback".