fix(sdk): Support design-time builds in Feersum SDK (#102)

* fix(sdk): Support design-time builds in Feersum SDK

Move language properties and ProjectCapability declarations into a
new Feersum.Sdk.props file, imported early from Sdk.props. This
ensures IDE project systems (VS, C# Dev Kit) see capabilities as
MSBuild items rather than a property string.

Guard CoreCompile's Exec and compiler-missing Error with
DesignTimeBuild conditions so IDEs can evaluate .scmproj projects
without running the full compiler. Touch a stub assembly during
design-time builds to satisfy downstream existence checks.

Update eng/ local-dev props to import the new Feersum.Sdk.props
so dogfood builds also get the capabilities.

* fix(sdk): address review feedback - quote Exists(), design-time stub path, pack props dir

Agent-Logs-Url: https://github.com/iwillspeak/feersum/sessions/44b09fdf-e5f2-4d01-82f5-ef9240abe8af

Co-authored-by: iwillspeak <[email protected]>

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Co-authored-by: copilot-swe-agent[bot] <[email protected]>
Co-authored-by: iwillspeak <[email protected]>

Feature/windows buildfix (#94)

* Fix Windows CI task to exit on build/test failures

* build: Expose Better Errors when Framework Resolution Fails

Currently the windows build looks to fail because it can't find the
types we need. This exposes better errors than the raw 'KeyNotFound'
which is all we have to go on right now.

* Include System.Core in core library references for .NET Framework compatibility

* Pass all framework references to compiler instead of filtering

* try 481?

* Explicitly include mscorlib from .NET Framework reference assemblies

* Restore framework/user library filtering while keeping mscorlib fix

* Potential fix for pull request finding

Co-authored-by: Copilot Autofix powered by AI <[email protected]>

* Fix type resolution to check ExportedTypes for forwarded types like System.Func`2

* fix: Resolve Exported Types

* back to baseline corelibref

* Pick to Resolve

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Co-authored-by: Copilot Autofix powered by AI <[email protected]>

Merge pull request #55 from iwillspeak/feature/newparse-full

Switch to New Parser

`.editorconfig` Improvements

Update code style for C#, and codify it in the eidtor config file.

Bump Docs and Templates for 0.2.6

It seems that aliasing the names of other installted templates wont't
work any more. The `--language` filter isn't enough to tell the
tmeplates apart it seems.

Fixup Build

Stop Dual-Targetting to avoid Flakiness

Macro Cond

Link Templates to Matching SDK

Generate Version even on `--no-build` (#33)

If `--no-build` is specified we currently don't generate the props file. Fix that by using `BeforeBuild instead.

Register as TFM Specific Pack File. It isn't really, but this ensures the file is always generated and evaluated for inclusion in the package.