refactor: init copilot-instructions and add OOP for manifests

[Alive-Fish]

https://msazure.visualstudio.com/Microsoft%20Teams%20Extensibility/_workitems/edit/36342436
https://msazure.visualstudio.com/Microsoft%20Teams%20Extensibility/_workitems/edit/36342483

[codecov]

Codecov Report

❌ Patch coverage is 90.52045% with 51 lines in your changes missing coverage. Please review.
✅ Project coverage is 89.20%. Comparing base (dbdf89d) to head (e384f59).
⚠️ Report is 10 commits behind head on dev.

Files with missing lines	Patch %	Lines
...st/src/wrappers/DeclarativeAgentManifestWrapper.ts	87.76%	9 Missing and 8 partials ⚠️
...ages/manifest/src/wrappers/TeamsManifestWrapper.ts	94.29%	3 Missing and 12 partials ⚠️
.../manifest/src/wrappers/APIPluginManifestWrapper.ts	89.62%	7 Missing and 4 partials ⚠️
packages/manifest/src/wrappers/BaseManifest.ts	73.33%	8 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##              dev   #15099      +/-   ##
==========================================
- Coverage   89.46%   89.20%   -0.26%     
==========================================
  Files         606      609       +3     
  Lines       37242    37691     +449     
  Branches     7619     7485     -134     
==========================================
+ Hits        33318    33622     +304     
- Misses       1837     1969     +132     
- Partials     2087     2100      +13     

Files with missing lines	Coverage Δ
packages/manifest/src/index.ts	0.00% <ø> (-86.28%)	⬇️
packages/manifest/src/manifest.ts	0.00% <ø> (-100.00%)	⬇️
packages/manifest/src/wrappers/BaseManifest.ts	73.33% <73.33%> (ø)
.../manifest/src/wrappers/APIPluginManifestWrapper.ts	89.62% <89.62%> (ø)
...ages/manifest/src/wrappers/TeamsManifestWrapper.ts	94.29% <94.29%> (ø)
...st/src/wrappers/DeclarativeAgentManifestWrapper.ts	87.76% <87.76%> (ø)

... and 20 files with indirect coverage changes

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