Feature: Auto-select token based on repository owner (multi-account support)

[lonecat13]

Problem

When working across multiple GitHub accounts or organizations (e.g., personal repos + work org), users currently need to either:

1. Run multiple MCP server instances with different tokens (leads to duplicate toolsets)
2. Manually switch tokens when context changes
3. Use a single token that may not have access to all repos they work with

This creates friction for developers who contribute to both personal projects and organization repositories.

Proposed Solution

Add support for automatic token selection based on the owner parameter in API calls.

Configuration

{
  "accounts": {
    "MagnetForensics": "ghp_org_token...",
    "coconutbird": "ghp_personal_token...",
    "*": "ghp_default_fallback..."
  }
}

Or via environment variables:

GITHUB_ACCOUNT_MAGNETFORENSICS=ghp_org_token...
GITHUB_ACCOUNT_COCONUTBIRD=ghp_personal_token...
GITHUB_PERSONAL_ACCESS_TOKEN=ghp_default_fallback...  # fallback

Behavior

• When a tool is called with owner: "MagnetForensics", use the mapped token
• When a tool is called with owner: "coconutbird", use that token
• Fall back to default/* token for unmapped owners
• For tools without an owner param (e.g., list_notifications), use the default token

Use Cases

1. Work + Personal - Developer uses personal GitHub for side projects, org account for work
2. Multiple orgs - Contractor working across several client organizations
3. Bot accounts - Using a bot token for CI-related operations, personal token for reviews
4. Scoped permissions - Read-only token for some orgs, full access for others

Alternatives Considered

• Running multiple server instances (works but duplicates all tools)
• Manual token switching (poor UX)
• GitHub App (more complex setup, not always feasible)