chore: fix VersionInfoProvider bugs, drop stale RegFree.targets entry, thin opsx prompts

[johnml1135]

Summary

• Extracted from PR Phase-1 base: Avalonia migration spine (UIMode defaults Legacy) #964 (phase1-base), where these three unrelated changes were bundled into the Avalonia migration PR.
• VersionInfoProvider.cs: fixes a stale hardcoded copyright year, a bug where ApplicationVersion always fell back to the entry assembly's version instead of the assembly it was actually built for, and defensive indexing in MajorVersion/ParseInformationalVersion to avoid a crash on an odd informational version string. Covered by new VersionInfoProviderTests.cs.
• Build/RegFree.targets: removes a dangling ManagedVwWindow.dll entry — that project was already retired in Reduce optional COM usage #904/Retire Linux-era view shims #906, so the entry pointed at a component that no longer exists.
• .github/prompts/opsx-*.prompt.md (10 files): replaces inlined instructions with delegation to the existing .claude/skills/openspec-*/SKILL.md files, consistent with this repo's skills-over-inline-prompts convention.

None of this is Avalonia-migration-specific; splitting it out so PR #964 stays scoped to the migration.

Test plan

• ./build.ps1 succeeds
• ./test.ps1 for FwUtilsTests (specifically VersionInfoProviderTests) passes
• Manual check: About box shows the current year's copyright

🤖 Generated with Claude Code

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This change is 

[github-actions]

NUnit Tests

    1 files  ±0      1 suites  ±0   10m 27s ⏱️ -12s
4 305 tests +6  4 232 ✅ +6  73 💤 ±0  0 ❌ ±0 
4 314 runs  +6  4 241 ✅ +6  73 💤 ±0  0 ❌ ±0 

Results for commit 0baae87. ± Comparison against base commit 4509530.

♻️ This comment has been updated with latest results.

[jasonleenaylor]

Looks good, Devin noted that ManagedVwWindow.dll was removed from RegFree.targets defaults but is still present in FieldWorks.exe BuildInclude.targets

@jasonleenaylor reviewed 14 files and all commit messages, and made 1 comment.
Reviewable status: complete! all files reviewed, all discussions resolved (waiting on johnml1135).

[johnml1135]

Code review (automated deep review, verified against the code)

Overall: the core VersionInfoProvider bug fixes are correct and well-tested — verified each against the real generated attribute shapes (ApplicationVersion now reads m_assembly rather than always the entry assembly; the trailing-space leak from the empty $FWBETAVERSION case is fixed by the IsNullOrWhiteSpace guard; MajorVersion no longer emits "9.3 STABILITY"/"9.3 "; copyright years are computed at runtime). The new VersionInfoProviderTests link the real CommonAssemblyInfo.cs, so they exercise the shipped attribute shapes. The 11 opsx stubs delegate to skill names that all map to existing .claude/skills/openspec-*/ dirs. Nice.

A few points:

MEDIUM — the RegFree cleanup is only half-done, and overlaps PR #989

This PR removes ManagedVwWindow.dll from Build/RegFree.targets, but that entry sits in the fallback ItemGroup gated by Condition="'@(ManagedComAssemblies)' == ''". For FieldWorks.exe the list is populated explicitly in Src/Common/FieldWorks/BuildInclude.targets:10 (which still contains <ManagedComAssemblies Include="$(OutDir)ManagedVwWindow.dll" />), so the fallback never applied to the main executable — it will keep emitting the Could not find file ...ManagedVwWindow.dll warning. The retire-linux-era-view-shims change (task 5.1, marked done) names both files; only RegFree.targets was done. Suggest also removing BuildInclude.targets:10 (and the stale CLSID-exclusion comment at Build/mkall.targets:46).

Also note: this RegFree.targets edit is the same line PR #989 removes (there it's replaced with an explanatory comment). The two PRs will conflict / one becomes a no-op — worth deciding which one carries the RegFree change and dropping it from the other. The removal is genuinely useful for LCMBrowser/GenerateHCConfig/UnicodeCharEditor/ComManifestTestHost, which hit the fallback path.

LOW / nit — const → static readonly is a (minor) binary-compat change

VersionInfoProvider.cs:23-28: kDefaultCopyrightString/kSensitiveCopyrightString are public and moved from const to static readonly. Necessary to compute the year at runtime, and I confirmed the only in-repo references are within VersionInfoProvider + the new test (no const-context/attribute/case usages), so it's safe here. Flagging only for public-API hygiene — an out-of-repo consumer that inlined the old const would need a recompile.

LOW — sensitive-mode copyright strip is literal

VersionInfoProvider.cs:305: copyRight.Replace("SIL International", string.Empty).TrimEnd(). Strips cleanly against today's fixed template (Copyright (c) 2002-$YEAR SIL International), but brittle if that string ever gains a trailing suffix (e.g. , Dallas), which would leak into "sensitive" output. Future fragility only.

Process note

The test-plan checkboxes (build.ps1, test.ps1 FwUtilsTests) are still unchecked, so passing tests aren't yet evidenced in the description.

_{Reviewed with Claude Code; findings verified against the code at the PR head. No code changed.}

[johnml1135]

Fixed the MEDIUM issue in 5b96437: removed the remaining ManagedVwWindow.dll entry from BuildInclude.targets (which pre-populates ManagedComAssemblies for FieldWorks.exe, bypassing the RegFree.targets fallback) and the matching stale CLSID exclusion in mkall.targets. The RegFree.targets overlap with #989 is moot now — #989 was closed as a duplicate.

Leaving the two LOW nits (const→static readonly, literal copyright strip) as documented trade-offs rather than churning the diff further; flag if you'd like those addressed too.