[Feature] Generate a single combined report across multiple .ecore files

[samatstariongroup]

Summary

Adds the ability to generate a single report (HTML, Markdown, Excel or model-inspection) that documents a multi-file Ecore metamodel, rather than one report per input file (fixes #89). The existing single-file behaviour is unchanged.

What is delivered

• Base (ReportGenerator): LoadRootPackages(FileInfo) (entry model plus every cross-referenced model reachable from it) and LoadRootPackages(DirectoryInfo) (every .ecore in a folder), both returning the root EPackage of every resource in one ResourceSet.
• Payload (HandleBarsReportGenerator): CreateHandlebarsPayload(IReadOnlyList<EPackage>) aggregates enums, primitive/other data types, classes and interfaces across all root packages; the single-package overload delegates to it.
• Generators: GenerateCombinedReport(...) overloads on HtmlReportGenerator, MarkdownReportGenerator, XlReportGenerator and ModelInspector — both the entry-reachable (FileInfo) and directory-wide (DirectoryInfo) shapes. The Excel info sheet gains an "Included Packages" row.
• Interfaces: IReportGenerator.GenerateCombinedReport(FileInfo, FileInfo) (drives the CLI polymorphically) plus format-specific directory/string overloads.
• CLI: --include-referenced-models / -r on every report command; when set the handler calls GenerateCombinedReport instead of GenerateReport.

Design notes

• Aggregation is exact — EPackage.QueryPackages() returns each root plus its containment subtree, and the file roots are disjoint, so there is no double counting.
• Cross-file references remain resolved (they are demand-loaded into the shared ResourceSet); the Overloaded EOperations produce duplicate cache keys; loading EMF's own Ecore.ecore crashes with ArgumentException #96/[Feature] Bring the HTML report generator to parity with uml4net #112 anchor scheme keeps anchors unique across files so intra-document links work in the combined HTML report.
• The directory shape reliably covers "all files"; the entry-reachable shape (the issue's least-intrusive suggestion) covers everything referenced from one entry and is what the CLI -r flag exposes.

Testing

• Full solution green (dotnet test EcoreNetto.sln): 338 tests.
• Combined-report tests against the full Eclipse Capella metamodel (21 files) for HTML, Markdown, Excel and inspection — a single output whose content originates from several different .ecore files; plus entry-reachable tests, a CLI -r handler test and null-guard tests.
• New combined-report code meets the >= 80% new-code coverage bar.

Acceptance criteria

• Single HTML report containing packages from all Capella files
• Single Excel report containing packages from all Capella files
• Single Markdown report containing packages from all Capella files
• Existing single-file behaviour unchanged
• Cross-file references remain resolved
• Tests cover the combined-report path (Capella), augmenting the per-file fixture

[samatstariongroup]

Added CLI directory mode (follow-up commit): the combined report can now be driven from the command line.

• -d / --input-directory <dir> produces one combined report for every .ecore in the directory (all files).
• -i <entry.ecore> -r / --include-referenced-models produces one combined report of the entry plus everything reachable from it.
• -i <entry.ecore> alone is unchanged (single-file report).

To make this polymorphic across all report types, GenerateCombinedReport(DirectoryInfo, FileInfo) was promoted to IReportGenerator (and implemented on the model inspector); --input-model is no longer required (either -i or -d). Covered by CLI handler tests.

[github-actions]

Package	Line Rate	Branch Rate	Complexity	Health
ECoreNetto	91%	87%	690	✔
ECoreNetto.Extensions	99%	92%	150	✔
ECoreNetto.HandleBars	99%	95%	102	✔
ECoreNetto.Reporting	89%	78%	397	✔
ECoreNetto.Tools	96%	93%	65	✔
Summary	92% (3603 / 3914)	86% (992 / 1160)	1404	✔

[sonarqubecloud]

Quality Gate failed

Failed conditions
3.5% Duplication on New Code (required ≤ 3%)

See analysis details on SonarQube Cloud