Add zero-config quick mode for thv vmcp serve

[yrobla]

Summary

When --config is omitted, --group enables quick mode: a minimal in-memory config is generated from the named ToolHive group so no config file is needed for the common local-aggregation case.

• Add GroupRef field to ServeConfig; Serve() branches on ConfigPath vs GroupRef vs neither (error)
• Add generateQuickModeConfig: anonymous auth, inline outgoing, prefix aggregation, validated before use
• Remove MarkFlagRequired("config"); add --group flag to serve command
• Regenerate docs/cli/thv_vmcp_serve.md

Fixes #4886

Type of change

• Bug fix
• New feature
• Refactoring (no behavior change)
• Dependency update
• Documentation
• Other (describe):

Test plan

• Unit tests (task test)
• E2E tests (task test-e2e)
• Linting (task lint-fix)
• Manual testing (describe below)

Changes

File	Change

Does this introduce a user-facing change?

Implementation plan

Approved implementation plan

Special notes for reviewers

[codecov]

Codecov Report

❌ Patch coverage is 72.91667% with 13 lines in your changes missing coverage. Please review.
✅ Project coverage is 69.39%. Comparing base (f5e0dbd) to head (14ca6b8).
⚠️ Report is 3 commits behind head on main.

Files with missing lines	Patch %	Lines
pkg/vmcp/cli/serve.go	72.91%	11 Missing and 2 partials ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #4913      +/-   ##
==========================================
- Coverage   69.40%   69.39%   -0.01%     
==========================================
  Files         538      539       +1     
  Lines       55494    55677     +183     
==========================================
+ Hits        38513    38636     +123     
- Misses      14023    14069      +46     
- Partials     2958     2972      +14     

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[Copilot]

Pull request overview

Adds a “zero-config quick mode” for thv vmcp serve so users can run the vMCP server without a YAML config by specifying --group, generating a minimal in-memory config for the common local aggregation workflow.

Changes:

• Extend ServeConfig with GroupRef and update Serve() to load config from --config or generate quick-mode config from --group.
• Add generateQuickModeConfig() helper and unit tests for quick-mode config generation and the “neither flag provided” error path.
• Update thv vmcp serve CLI flags/docs: remove required --config, add --group, regenerate command docs.

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 4 comments.

File	Description
pkg/vmcp/cli/serve.go	Adds GroupRef quick-mode branching and helper to generate/validate an in-memory config.
pkg/vmcp/cli/serve_test.go	Adds tests for quick-mode config generation and for erroring when neither --config nor --group is provided.
cmd/thv/app/vmcp.go	Updates Cobra command flags: --config no longer required; adds --group and passes it to Serve().
docs/cli/thv_vmcp_serve.md	Documents quick mode and updates the options list to include --group.

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The base branch was changed.

[Copilot]

Pull request overview

Copilot reviewed 4 out of 4 changed files in this pull request and generated 2 comments.

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[Copilot]

Pull request overview

Copilot reviewed 4 out of 4 changed files in this pull request and generated 3 comments.

---

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