📝 Add docstrings to feat/go-rewrite

Docstrings generation was requested by @blakeridgway.

* https://github.com/RideAware/admin-panel/pull/1#issuecomment-3528008426

The following files were modified:

* `cmd/admin-panel/main.go`
* `internal/config/config.go`
* `internal/database/database.go`
* `internal/email/email.go`
* `internal/handlers/auth.go`
* `internal/handlers/newsletter.go`
* `internal/handlers/subscribers.go`
* `internal/middleware/auth.go`

internal/handlers/subscribers.go

@@ -8,6 +8,9 @@ import (
 	"github.com/gin-gonic/gin"
 )
 
+// IndexGet handles requests for the admin index page by retrieving all subscriber emails
+// and rendering the "admin_index.html" template with those emails.
+// If retrieving emails fails, it aborts the request with HTTP 500 and the error.
 func IndexGet(c *gin.Context) {
 	emails, err := database.GetAllEmails()
 	if err != nil {