feat: update App Manifest version to v1.26 across all templates

[Copilot]

Bumps the Teams App Manifest schema from v1.25 to v1.26 across all templates, incorporating the new schema changes: description.features array, oAuth2.0 auth type for compose extensions, oAuthConfiguration object, and relaxed copilotAgents validation (empty anyOf replacing oneOf).

Template updates (123 files)

• "manifestVersion": "1.25" → "1.26"
• $schema URL: .../v1.25/MicrosoftTeams.schema.json → .../v1.26/...

packages/manifest — new v1.26 schema + generated types

• Added src/json-schemas/teams/v1.26/ with all 4 schema files from Microsoft's developer portal
• Applied two fixes to the downloaded schema before code generation:
  • manifestVersion const: Published v1.26 schema incorrectly still says "1.25" — corrected to "1.26" in our local copy
  • copilotAgents.anyOf: Empty anyOf: [] (the schema change from oneOf) causes a quicktype codegen error ("impossible type"); removed it to allow type generation while preserving the structural properties
• Regenerated TeamsManifestV1D26.ts via npm run convert
• Updated generated-types/index.ts: added v1.26 to the TeamsManifest union, converter map, and set TeamsManifestLatest = TeamsManifestV1D26

packages/mcp-server

• fetcher.ts: latestVersion: "v1.25" → "v1.26" for app_manifest
• fetcher.test.ts: updated expected schema URL accordingly

Original prompt

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This section details on the original issue you should resolve

<issue_title>Update App Manifest Version to v1.26 in each template</issue_title>
<issue_description># App Manifest Schema Update v1.26

Latest Schema Commit: b919047

🎯 Impacted Properties We Support

The following properties used in our templates have been updated and require attention:

description ✅ NON-BREAKING

Change: Added a 'features' array property with required 'title' and 'description' fields, each with max length constraints and a minimum/maximum number of items.

Impact: Business logic that populates or validates 'description' will now need to handle the 'features' array, ensuring each feature meets the new constraints. This could require UI, validation, or data model changes to support the new structure.

composeExtensions.authorization.authType ✅ NON-BREAKING

Change: Added 'oAuth2.0' to the enum list for 'authType'.

Impact: Integration logic must handle the new 'oAuth2.0' type, which may require additional logic to support OAuth flows where previously unsupported.

composeExtensions.authorization.oAuthConfiguration ✅ NON-BREAKING

Change: Added new 'oAuthConfiguration' object, required when 'authType' is 'oAuth2.0', with a required 'oAuthConfigurationId' string.

Impact: When using 'oAuth2.0', business logic must now provide and validate an 'oAuthConfiguration' object, impacting how OAuth integrations are configured and validated.

copilotAgents ✅ NON-BREAKING

Change: Changed from 'oneOf' with required 'declarativeAgents' or 'customEngineAgents' to an empty 'anyOf' array.

Impact: Validation logic for 'copilotAgents' will change; the schema no longer enforces the presence of specific agent types, potentially allowing more flexible or less constrained agent definitions. This may require updates to ensure business rules are still enforced.

📋 Action Required

Please update the following files in each template repository:

• manifest.json.tpl
• manifest.local.json.tpl (if applicable)
• manifest.dev.json.tpl (if applicable)

Note: Ensure all impacted properties listed above are properly updated according to the new schema requirements.

🔗 Related Work Item

Azure DevOps Work Item

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This issue was automatically generated by the Dependency Manager.</issue_description>

Comments on the Issue (you are @copilot in this section)

• Fixes Update App Manifest Version to v1.26 in each template #15547

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 92.77%. Comparing base (af65c62) to head (ad7a1de).
⚠️ Report is 47 commits behind head on dev.

Additional details and impacted files

@@            Coverage Diff             @@
##              dev   #15578      +/-   ##
==========================================
+ Coverage   89.26%   92.77%   +3.50%     
==========================================
  Files         622      622              
  Lines       38107    38119      +12     
  Branches     7560     7042     -518     
==========================================
+ Hits        34015    35363    +1348     
- Misses       1987     2020      +33     
+ Partials     2105      736    -1369     

Files with missing lines	Coverage Δ
packages/mcp-server/src/fetcher.ts	100.00% <ø> (ø)

... and 307 files with indirect coverage changes

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