feat: Add additional verification APIs (FCA, SRA, GitHub, OpenCorporates, ORCID)

This adds five new free API integrations for enhanced CV verification:

- FCA Register API: Verify financial services professionals
- SRA Register API: Verify solicitors and legal professionals
- GitHub API: Verify developer profiles and technical skills
- OpenCorporates API: Verify international companies across jurisdictions
- ORCID API: Verify academic researchers and publications

Includes:
- API clients for all five services with retry policies
- Service implementations with name matching and validation
- Models for verification results with detailed flags
- Configuration options in appsettings.json
- DI registration for all services

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

src/RealCV.Application/Interfaces/IGitHubVerifierService.cs

@@ -0,0 +1,36 @@
+using RealCV.Application.Models;
+
+namespace RealCV.Application.Interfaces;
+
+/// <summary>
+/// Service for verifying developer profiles and skills via GitHub
+/// </summary>
+public interface IGitHubVerifierService
+{
+    /// <summary>
+    /// Verify a GitHub profile and analyze activity
+    /// </summary>
+    Task<GitHubVerificationResult> VerifyProfileAsync(string username);
+
+    /// <summary>
+    /// Verify claimed programming skills against GitHub activity
+    /// </summary>
+    Task<GitHubVerificationResult> VerifySkillsAsync(
+        string username,
+        List<string> claimedSkills);
+
+    /// <summary>
+    /// Search for GitHub profiles matching a name
+    /// </summary>
+    Task<List<GitHubProfileSearchResult>> SearchProfilesAsync(string name);
+}
+
+public sealed record GitHubProfileSearchResult
+{
+    public required string Username { get; init; }
+    public string? Name { get; init; }
+    public string? AvatarUrl { get; init; }
+    public string? Bio { get; init; }
+    public int PublicRepos { get; init; }
+    public int Followers { get; init; }
+}