feat(cli): Enable PublishTrimmed for Cli.Embedded (Phase 2 of #40)

[kirkone]

Goal

Enable PublishTrimmed=true for Cli.Embedded to reduce the standalone binary size.
This is Phase 2 of #40 — the static-link build is done, but actual trimming was never enabled.

Baseline

• Current Cli.Embedded single-file size: 46.5 MB (Brotli compressed)
• Expected after trimming: 25-35 MB (~30-40% reduction)

Investigation Results

A test build with PublishTrimmed=true + TrimMode=partial revealed 45 trim issues — all in our own code:

Category	Count	API
JsonSerializer without source-gen	27	IL2026
LINQ Expression building	8	IL2026 (Expression.Property)
MakeGenericMethod	1	IL2060

Good news: Scriban, NetVips, Spectre.Console, System.CommandLine, Microsoft.Extensions.* are all trim-compatible. No third-party blockers.

Tasks

Phase 1: Foundation

• Add EnableTrimAnalyzer=true to Core, Features/Generate, Features/Packages (will surface remaining issues)

Phase 2: JSON Source Generators (27 occurrences)

Replace untyped JsonSerializer.Serialize/Deserialize with [JsonSerializable] source-gen contexts.

Already done (5 contexts): PackageIndex, ThemeJsonConfig, NuGetSearch, Statistics, OneDrive, Calendar.

Remaining:

• Core/Services/GlobalConfigManager (Load + Save)
• Core/Themes/LocalThemeProvider
• Features/Generate/Services/ManifestService (Load + Save)
• Features/Generate/Services/RenderService.ResolveSingleDataSourceAsync
• Features/Generate/Commands/ConfigImageCommand.LoadThemeDefaults
• Other RefreshCommand JSON paths (some still untyped)

Phase 3: LINQ Expression Builder (8 occurrences)

• Analyze Features/Generate/Filtering/FilterExpressionBuilder — Expression.Property(expr, name) is fundamentally trim-unsafe (uses reflection at runtime)
• Options: annotate with [DynamicallyAccessedMembers], restructure to use typed accessors, or replace with source-generated filter compiler

Phase 4: MakeGenericMethod (1 occurrence)

• Features/Generate/Commands/CreatePageCommand.ExtractValues — annotate with DynamicallyAccessedMembersAttribute or restructure

Phase 5: Activate Trimming

• Set PublishTrimmed=true + TrimMode=partial in Cli.Embedded.csproj
• Smoke-test all commands (generate, theme, plugin, project, config, source, …)
• Test interactive menu
• Test theme extract
• Test image processing pipeline end-to-end
• Measure final size

Phase 6: Pipeline

• Add PublishTrimmed to release.yml Standalone publish step
• Add PublishTrimmed to ci.yml smoke-test (catches regressions early)
• Update release notes with size info

References

• Closes Phase 2 of feat(cli): Embedded AOT Build — statisch gelinkte Executable ohne Runtime-Plugin-Loading #40
• Builds on feat(sdk): Plugins AOT- und Trimming-kompatibel machen #39 (IsTrimmable foundation in Plugins/SDK)

Strategy

Work in small, testable steps — each phase should land as a separate PR. Do NOT enable PublishTrimmed until all analyzer issues are resolved, otherwise we trade compile-time errors for runtime crashes.