[Sprint 19] feat(app): auto-fill Author when creating a new blog post

[mpaulosky]

When we are creating a new Post we should auto fill the Author with the logged in users info

• The Author should be an object

• The Author object should include

• User's Id

• Users name

• Users Email

• Users Roles

This will help control when a user wants to edit a Post only the Admin and Author roles can edit but Authors can only edit the Posts they Authored.

[github-actions]

📋 Assigned to Legolas (Frontend / Blazor)

Issue: #296 — When Creating a new Post we should Auto fill the Author

Legolas will pick this up in the next Copilot session.

For Copilot coding agent: If enabled, this issue will be worked automatically.
Otherwise, start a Copilot session and say:
Legolas, work on issue #296

[github-actions]

🏗️ Squad Triage — Aragorn (Lead / Architect)

Issue: #296 — When Creating a new Post we should Auto fill the Author
Assigned to: Sam (Backend / .NET)
Reason: Issue relates to backend/API work

Team roster:

• Aragorn (Lead / Architect) → label: squad:aragorn
• Sam (Backend / .NET) → label: squad:sam
• Legolas (Frontend / Blazor) → label: squad:legolas
• Gimli (Tester) → label: squad:gimli
• Boromir (DevOps / Infra) → label: squad:boromir
• Gandalf (Security / Auth) → label: squad:gandalf
• Frodo (Tech Writer) → label: squad:frodo
• Pippin (Docs) → label: squad:pippin
• Bilbo (Tech Blogger) → label: squad:bilbo
• Ralph (Meta) → label: squad:ralph

To reassign, remove the current squad:* label and add the correct one.

[github-actions]

📋 Assigned to Aragorn (Lead / Architect)

Issue: #296 — When Creating a new Post we should Auto fill the Author

Aragorn will pick this up in the next Copilot session.

For Copilot coding agent: If enabled, this issue will be worked automatically.
Otherwise, start a Copilot session and say:
Aragorn, work on issue #296

[mpaulosky]

Architecture Review (Aragorn):

Replace string Author on BlogPost with a PostAuthor value object (Id, Name, Email, Roles). The Blazor component reads the logged-in user's claims (sub, name, email, via RoleClaimsHelper.GetRoles) and passes a fully-built PostAuthor into CreateBlogPostCommand — the handler stays infrastructure-agnostic.

Key decisions:

• PostAuthor lives in MyBlog.Domain.ValueObjects as an immutable record
• Stored as an embedded document in MongoDB via EF Core OwnsOne
• BlogPostDto gets flat fields: AuthorId, AuthorName, AuthorEmail, AuthorRoles
• Author is immutable after creation — edit flow unchanged
• IHttpContextAccessor NOT injected into handler (unreliable in Blazor Server SignalR mode — auth state read in the component instead)
• ⚠️ Breaking MongoDB schema change: existing Author: "string" documents must be migrated; drop/recreate in dev, follow-up issue for production migration
• 🚫 "Authors can only edit their own posts" access-control check is out of scope — new issue needed

Implementation plan:

• Sam (backend): PostAuthor.cs (new), BlogPost.cs, BlogDbContext.cs, BlogPostDto.cs, BlogPostMappings.cs, CreateBlogPostCommand.cs, CreateBlogPostCommandValidator.cs, CreateBlogPostHandler.cs (no logic change)
• Legolas (UI): Create.razor (remove Author input, inject AuthStateProvider, build PostAuthor from claims, show read-only author name), Index.razor / Edit.razor (update dto.Author → dto.AuthorName)
• Gimli (tests): All BlogPost create tests, handler tests, validator tests, mapping tests, integration repo tests — update to use PostAuthor object instead of string

ADR written to .squad/decisions/inbox/aragorn-296-post-author-adr.md. Branch: squad/296-post-author-value-object.