refactor(api): migrate console installed-app list response to BaseModel

[ai-hpc]

Part of #28015

Summary

Migrate console installed-app list response from Flask-RESTX @marshal_with to Pydantic BaseModel response schemas. Add explicit installed-app/app DTOs (including computed icon_url and timestamp normalization) and keep filtering/sorting behavior unchanged.

Checklist

• This change requires a documentation update, included: Dify Document
• I understand that this PR may be closed in case there was no previous discussion or issues. (This doesn't apply to typos!)
• I've added a test for each change that was introduced, and I tried as much as possible to make a single atomic change.
• I've updated the documentation accordingly.
• I ran make lint and make type-check (backend) and cd web && pnpm exec vp staged (frontend) to appease the lint gods

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Pull request overview

Migrates the console “installed apps list” endpoint response from Flask-RESTX @marshal_with field-based schemas to Pydantic BaseModel-based response schemas, keeping existing filtering/sorting logic while adding explicit DTOs (including icon_url computation and timestamp normalization).

Changes:

• Introduces Pydantic response models for installed-app listing (InstalledAppInfoResponse, InstalledAppResponse, InstalledAppListResponse).
• Replaces @marshal_with(...) with a Pydantic-validated + model_dump(mode="json") response and registers schemas for Swagger.
• Adds icon_url as a computed field and normalizes last_used_at to an integer timestamp.

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Pyrefly Diff

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