Ensure copied Mockly skill content is ignored in consuming repos

[Copilot]

When Mockly copies its bundled skill into a consuming repository during build, the copied files can appear as untracked source-control noise. This change makes the generated skill directory self-ignoring by shipping and copying a .gitignore with the skill.

• Package payload update

  • Added Mockly/skill.gitignore and packed it as skills/mockly/.gitignore in the NuGet package.
  • Updated Mockly.csproj package item definitions so the ignore file is distributed with the existing SKILL.md.

• Build-transitive copy behavior

  • Extended Mockly.targets to copy .gitignore into .agents/skills/mockly alongside SKILL.md.
  • Preserved existing repo-root resolution and opt-out behavior (MocklySkill=false).

• Resulting generated ignore rule

  *
  !.gitignore

[github-actions]

Test Results

  3 files  ±0    3 suites  ±0   9s ⏱️ +3s
155 tests ±0  155 ✅ ±0  0 💤 ±0  0 ❌ ±0 
307 runs  ±0  307 ✅ ±0  0 💤 ±0  0 ❌ ±0 

Results for commit e664a62. ± Comparison against base commit c27fdf7.

♻️ This comment has been updated with latest results.

[coveralls]

Coverage Report for CI Build 26818785079

Coverage remained the same at 84.624%

Details

• Coverage remained the same as the base build.
• Patch coverage: No coverable lines changed in this PR.
• No coverage regressions found.

Uncovered Changes

No uncovered changes found.

Coverage Regressions

No coverage regressions found.

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Coverage Stats

Relevant Lines:	1322
Covered Lines:	1186
Line Coverage:	89.71%
Relevant Branches:	447
Covered Branches:	311
Branch Coverage:	69.57%
Branches in Coverage %:	Yes
Coverage Strength:	283.12 hits per line

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💛 - Coveralls