Enforce full analyzer set with warnings as errors

[ptr727]

Summary

ProjectTemplate#353 downstream - the dedicated analyzer PR of the issue #14 convergence sequence (item 2 of the curated addendum).

• Remove the dotnet_analyzer_diagnostic.severity = suggestion downgrade from .editorconfig.
• Add Directory.Build.props with the fleet-standard analyzer block (TreatWarningsAsErrors=true, AnalysisMode=All, AnalysisLevel=latest-all, EnableNETAnalyzers), and dedupe the hoisted common properties from the three csproj files.
• xUnit1051 (180 sites): every async call in the test suite now passes TestContext.Current.CancellationToken, so xUnit v3 can cancel a stalled test. Passed as a named argument where calls carry other arguments (several target methods have intermediate optional parameters). Two sites that already passed default positionally were converted rather than appended.
• xUnit1030 (1 site): stray .ConfigureAwait(false) removed from a test.
• CS8625 (2 sites): benchmarks passed null for the non-nullable sha1 column - fixed with real hash values (computed for the seed record, synthesized for the insert loop), not a null-forgiving operator.
• Surfaced by full enforcement, fixed at the source:MediaBenchmarks implements IAsyncDisposable (CA1001/CA1816) and stays unsealed (BDN1002); the unreadable-key-file test uses a platform guard CA1416's flow analysis recognizes (Assert.SkipWhen is invisible to it), behavior unchanged.
• Structural can't-fix rules relaxed per the established per-project pattern: new PhotoCleanerBenchmarks/.editorconfig for CA2007 (harness code, no sync context - same rationale as the tests project) and CA1515 (BenchmarkDotNet requires public, unsealed classes).
• SQLite/NU1903 needed no change here - resolved on develop by Add --apikey-file for trash and update all dependencies #15; the zero-warning build confirms.

Testing

• Build is zero-warning / zero-error across all three projects under full enforcement.
• dotnet format style --verify-no-changes: clean. editorconfig-checker: exit 0.
• Full test suite: 324/324 pass.

🤖 Generated with Claude Code

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 44.96%. Comparing base (50a524e) to head (adb224b).

Additional details and impacted files

@@ Coverage Diff @@## develop #17 +/- ##
========================================
Coverage 44.96% 44.96% ========================================
Files 25 25 Lines 3398 3398 Branches 259 259 ========================================
Hits 1528 1528 Misses 1824 1824 Partials 46 46 

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[Copilot]

Pull request overview

This PR tightens build-time code quality enforcement across the solution by enabling the full .NET analyzer set and treating warnings as errors, then updating projects/tests/benchmarks to comply (notably xUnit v3 cancellation support and benchmark analyzer relaxations).

Changes:

• Add Directory.Build.props to centralize common project properties and enable full analyzers with warnings-as-errors; remove the .editorconfig analyzer downgrade.
• Update the xUnit test suite to pass TestContext.Current.CancellationToken through async call chains and remove a stray .ConfigureAwait(false) in a test.
• Fix benchmark code to satisfy analyzer requirements (non-null sha1, implement IAsyncDisposable) and add a benchmarks-specific .editorconfig to relax structurally incompatible rules.

Reviewed changes

Copilot reviewed 15 out of 15 changed files in this pull request and generated 4 comments.

Show a summary per file

File	Description
Directory.Build.props	Centralizes analyzer + common MSBuild properties (TFM, nullable, WAE, analysis mode/level).
.editorconfig	Removes global analyzer severity downgrade to allow full enforcement.
PhotoCleaner/PhotoCleaner.csproj	Removes duplicated analyzer/common properties now provided by Directory.Build.props.
PhotoCleanerTests/PhotoCleanerTests.csproj	Removes duplicated common properties now provided by Directory.Build.props.
PhotoCleanerBenchmarks/PhotoCleanerBenchmarks.csproj	Removes duplicated common properties now provided by Directory.Build.props.
PhotoCleanerBenchmarks/.editorconfig	Per-project relaxations for benchmark harness constraints (CA1515/CA2007).
PhotoCleanerBenchmarks/MediaBenchmarks.cs	Avoids null sha1 inserts and adds async disposal to satisfy analyzer requirements.
PhotoCleanerTests/UndoTaskTests.cs	Passes xUnit cancellation token into UndoTask.Execute(...) calls.
PhotoCleanerTests/TrashDatabaseTests.cs	Threads xUnit cancellation token through Trash DB async calls.
PhotoCleanerTests/TrashCommandTests.cs	Threads xUnit cancellation token through Trash DB verification calls.
PhotoCleanerTests/ProcessTaskTests.cs	Adds xUnit cancellation token to async I/O + DB/trash DB calls in tests.
PhotoCleanerTests/IndexTaskTests.cs	Threads xUnit cancellation token through index-task and DB calls.
PhotoCleanerTests/ImportTaskTests.cs	Threads xUnit cancellation token through hashing/DB/exiftool calls.
PhotoCleanerTests/DatabaseTests.cs	Threads xUnit cancellation token through DB and file I/O calls.
PhotoCleanerTests/CommandLineTests.cs	Reworks the unreadable-key-file test to use a platform guard analyzers can understand.

[Copilot]

Pull request overview

Copilot reviewed 15 out of 15 changed files in this pull request and generated 2 comments.

[Copilot]

Pull request overview

Copilot reviewed 15 out of 15 changed files in this pull request and generated no new comments.