feat(shared): create Shared class library (#2)

.ai-team/agents/aragorn/history.md

@@ -27,4 +27,21 @@
 
 ## Learnings
 
-*Append new patterns, MongoDB insights, and backend decisions here as you work.*
+### Issue #2 — Shared Library Implementation (2026-02-17)
+
+**Completed:**
+- Created `IssueManager.Shared` class library (net10.0, C# 14.0)
+- Registered in IssueManager.slnx solution file
+- Zero external NuGet dependencies (only .NET BCL)
+- Placeholder Utilities.cs class for compileability
+
+**Patterns Established:**
+- Shared library will grow organically (no premature structure)
+- Content areas: DTOs, Extensions, Constants, Validators, Domain enums, Result types
+- Vertical slices consume Shared selectively — no forced coupling
+
+**Technical Details:**
+- Project config matches ServiceDefaults/Api/Web conventions
+- Nullable enabled, ImplicitUsings enabled
+- RootNamespace: `IssueManager.Shared`
+- Shared csproj uses no dependencies beyond Directory.Packages.props

.ai-team/decisions/inbox/aragorn-shared-library-design.md

@@ -0,0 +1,60 @@
+# Decision — Shared Library Structure
+
+**Date:** 2026-02-17  
+**By:** Aragorn  
+**Decision:** Design of the IssueManager.Shared library
+
+## Context
+
+Issue #2 required creation of a new `Shared` class library to serve as a common dependency across vertical slices. The library needed to follow the same conventions as existing projects (ServiceDefaults, Api, Web).
+
+## Decision
+
+### Project Structure
+
+**Location:** `src/Shared/`  
+**Name:** `IssueManager.Shared`  
+**Target Framework:** `.NET 10.0`  
+**Language Version:** `C# 14.0`
+
+### Configuration
+
+The Shared project uses standard .NET conventions:
+- `Nullable` enabled for null-safety
+- `ImplicitUsings` enabled for cleaner code
+- Root namespace: `IssueManager.Shared`
+- No external NuGet dependencies (uses only .NET BCL)
+
+### Content Strategy
+
+The library begins with a placeholder `Utilities.cs` class. As features are built, the Shared library will contain:
+
+1. **Common DTOs** — Shared request/response types across vertical slices
+2. **Extensions** — Extension methods for common operations
+3. **Constants** — Application-wide configuration constants
+4. **Validation Rules** — Reusable FluentValidation rules
+5. **Domain Types** — Shared enums (e.g., IssueStatus, IssuePriority)
+6. **Result Types** — Standard Result<T> or OneOf<T> for consistent error handling
+
+### Dependency Management
+
+The Shared library has **zero external dependencies**. It depends only on:
+- .NET 10.0 runtime
+- C# 14.0 language features
+
+This keeps the library lightweight and ensures no dependency bloat for consuming projects.
+
+### No Structure Enforcement Yet
+
+Subdirectories (Extensions/, Validators/, Models/, Constants/) can be created as needed per feature. Premature structure causes friction; we'll organize organically as code grows.
+
+## Rationale
+
+1. **Vertical Slice Safety** — Shared library does NOT enforce cross-slice dependencies. Slices use only what they need.
+2. **No Bloat** — Zero external dependencies makes Shared fast and reliable.
+3. **Growth Path** — Structure will emerge naturally as patterns appear.
+4. **Convention Consistency** — Uses same csproj conventions as ServiceDefaults, Api, and Web.
+
+## Status
+
+✅ **Accepted**

IssueManager.slnx

@@ -6,6 +6,7 @@
   "projects": [
     "src/AppHost/AppHost.csproj",
     "src/ServiceDefaults/ServiceDefaults.csproj",
+    "src/Shared/Shared.csproj",
     "src/Api/Api.csproj",
     "src/Web/Web.csproj"
   ]

src/Shared/Shared.csproj

@@ -0,0 +1,9 @@
+<Project Sdk="Microsoft.NET.Sdk">
+	<PropertyGroup>
+		<TargetFramework>net10.0</TargetFramework>
+		<LangVersion>14.0</LangVersion>
+		<Nullable>enable</Nullable>
+		<ImplicitUsings>enable</ImplicitUsings>
+		<RootNamespace>IssueManager.Shared</RootNamespace>
+	</PropertyGroup>
+</Project>

src/Shared/Utilities.cs

@@ -0,0 +1,9 @@
+namespace IssueManager.Shared;
+
+/// <summary>
+/// Placeholder utilities class for the Shared library.
+/// This class serves as an entry point for shared utilities and extensions across the IssueManager project.
+/// </summary>
+public static class Utilities
+{
+}