Add per-table emitter configuration for spec-dashboard

[Copilot]

Some languages like C# require different emitters for management plane vs data plane scenarios. Currently, emitterNames is only configurable globally in CoverageFromAzureStorageOptions, preventing mixed-emitter table configurations.

Changes

• Added optional emitterNames?: string[] field to TableDefinition interface
• Modified splitManifestByTables() to propagate table-specific emitter names through the pipeline
• Updated getCoverageSummaries() to:
  • Collect union of global and table-specific emitters
  • Load all required reports in single batch
  • Filter reports per table using table-specific emitters when present, falling back to global options.emitterNames otherwise
• Refactored loadReports() to accept emitter names as parameter

Example

const options: CoverageFromAzureStorageOptions = {
  storageAccountName: "account",
  containerName: "coverage",
  manifestContainerName: "manifests",
  emitterNames: ["@typespec/default"],
  tables: [
    {
      name: "Management Plane",
      packageName: "my-package",
      prefixes: ["mgmt_"],
      emitterNames: ["@azure-tools/typespec-csharp-mgmt"]  // Override for mgmt scenarios
    },
    {
      name: "Data Plane", 
      packageName: "my-package",
      prefixes: ["dataplane_"],
      emitterNames: ["@azure-tools/typespec-csharp"]  // Override for data plane
    }
  ]
};

Original prompt

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This section details on the original issue you should resolve

<issue_title>Add ability to specify emitters per table</issue_title>
<issue_description>In some languages, like C#, we have different emitters for mgmt vs data plane scenarios. We should be able to specify the emitterNames in the TableDefinitions in CoverageFromAzureStorageOptions. If a table has emitter names we use that, otherwise fall back to global defaults.</issue_description>

Comments on the Issue (you are @copilot in this section)

• Fixes Add ability to specify emitters per table #9053

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[github-actions]

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