Add compiler log (.complog) support as a website generation input

[jaredpar]

Why

The indexer currently accepts MSBuild binlogs and .sln/.slnx files as inputs. Compiler logs (.complog, from jaredpar/complog) are a compact, self-contained format that captures a fully-resolved Roslyn compilation per project. Supporting them lets repos feed the source browser without needing MSBuild evaluation at index time.

Approach

A .complog behaves like a workspace-producing input (similar to .sln), not like the binlog invocation-extraction path, so it is routed through SolutionGenerator/the Roslyn workspace rather than IndexSolutionsAsync's binlog branch.

• Workspace creation (SolutionGenerator): Basic.CompilerLog.Util.SolutionReader materializes a SolutionInfo directly. It is created with BasicAnalyzerKind.None so originally-generated files are added inline and analyzers/source generators are not re-run. The reader is kept alive for the duration of Pass1 because document source text is loaded lazily from it, and is disposed in Dispose().
• Assembly names (Program.GetAssemblyNamesAsync): read via the lighter-weight CompilerLogReader (ReadCompilerCallData(cc).AssemblyFileName for Regular calls) instead of building a full solution.
• Type forwards (Program.GetTypeForwards): a compiler log does not ship emitted binaries, so each project's assembly is re-emitted to memory (EmitToMemory(EmitFlags.MetadataOnly)) from the persisted compilation and the forwards are read from those bytes. TypeForwardReader gained a Stream overload for this, sharing the metadata walk with the existing file-based path.
• Naming quirk: complog reports AssemblyName with the file extension (e.g. HelloLib.dll), unlike the binlog/Roslyn path. NormalizeCompilerLogAssemblyNames strips it so Pass1 output folders line up with the extension-less global assembly list.
• Plumbing: CommandLineOptions.IsSupportedProject and the README accept/document .complog; index.proj discovers and indexes *.complog in the pipeline.

Notes for reviewers

• During generation complog emits a benign first-chance IOException on its locks\*.lock files; it is handled internally and generation completes fine.
• Microsoft.CodeAnalysis.SolutionInfo is referenced fully-qualified in a couple of spots on purpose: HtmlGenerator has its own Microsoft.SourceBrowser.HtmlGenerator.SolutionInfo type that otherwise makes the short name ambiguous.

Validation

• HtmlGenerator builds clean; all 189 tests pass (including new assembly-name normalization tests).
• Verified end-to-end: built a C# lib to a binlog, converted to .complog, ran HtmlGenerator on it. Source is indexed and the output structure matches the equivalent binlog run (extension-less HelloLib folder).