refactor(config): centralize stdio server type helpers

[Copilot]

The "is stdio" predicate (t == "" || t == "stdio" || t == "local") and the normalization pattern were duplicated across 7 sites in 3 files, with one site (validateStandardServerConfig) missing the "" case — a silent validation gap.

Changes

• internal/config/server_type.go — new file with two helpers:

  • IsStdioServerType(t string) bool — canonical check covering "", "stdio", "local"
  • NormalizeServerType(t string) string — maps "" / "local" → "stdio", passes rest through

• validation.go — 3 sites updated:

  • Normalization block collapsed from two if checks to one NormalizeServerType call
  • validateStandardServerConfig (line 62): "stdio" || "local" → IsStdioServerType (also fixes the missing "" case)
  • validateTOMLStdioContainerization (line 489): triple OR → IsStdioServerType

• config_stdin.go — 4-line normalization block replaced with single NormalizeServerType call

• validation_schema.go — triple OR in validateStringPatterns replaced with IsStdioServerType

• internal/config/server_type_test.go — table-driven tests for both helpers covering all type values including wrong-case strings

// Before (repeated 5× across 3 files):
if cfg.Type == "" || cfg.Type == "stdio" || cfg.Type == "local" { ... }

// After:
if IsStdioServerType(cfg.Type) { ... }

[lpcox]

@copilot resolve the merge conflicts in this pull request

[Copilot]

Pull request overview

This PR centralizes the “stdio-family” server type predicate and normalization logic in internal/config, removing duplicated checks and fixing a validation gap where an empty type wasn’t treated as stdio in one validation path.

Changes:

• Added IsStdioServerType and NormalizeServerType helpers to canonicalize stdio-type handling.
• Replaced repeated "" || "stdio" || "local" checks with IsStdioServerType in validation and schema validation.
• Added table-driven unit tests for the new helpers.

Show a summary per file

File	Description
internal/config/server_type.go	Introduces centralized stdio-type predicate + normalization helpers.
internal/config/server_type_test.go	Adds unit coverage for helper behavior across expected/edge inputs.
internal/config/validation.go	Uses helpers to normalize types and consistently enforce stdio container requirements.
internal/config/validation_schema.go	Uses helper for stdio container-pattern validation.
internal/config/config_stdin.go	Uses normalization helper when converting stdin server configs.

Copilot's findings

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Comments suppressed due to low confidence (1)

internal/config/validation.go:60

• This change fixes a validation gap: an empty server type now correctly behaves like stdio and requires container. There doesn't appear to be a regression test covering the failing case (Type == "" with missing container) in internal/config/validation_test.go; adding one would prevent reintroducing this silent acceptance.

	if IsStdioServerType(server.Type) {
		if server.Container == "" {
			logValidation.Printf("Validation failed: %s, name=%s, type=%s", "stdio server missing container field", name, server.Type)
			return MissingRequired("container", "stdio", jsonPath, "Add a 'container' field (e.g., \"ghcr.io/owner/image:tag\")")
		}

• Files reviewed: 5/5 changed files
• Comments generated: 1

[Copilot]

@copilot resolve the merge conflicts in this pull request

Resolved. The only conflict was in config_stdin.go — I kept the main branch's approach of using server.Type directly (with its accurate comment noting both "" and "local" are normalized to "stdio" by validateServerConfigWithCustomSchemas upstream). The merge also picks up the UnsupportedField → InvalidValue consolidation from main. All tests pass.