feat: redirect root path based on auth state (#52)

Closes #51

The root path `/` now checks for an authenticated session and redirects accordingly:

- **Authenticated users** → `303 See Other` redirect to `/sources` (the webhook dashboard)
- **Unauthenticated users** → `303 See Other` redirect to `/pages/login`

### Changes

- **`internal/handlers/index.go`** — Replaced the template-rendering `HandleIndex()` with a session-checking redirect handler. Removed `formatUptime` helper (dead code after this change).
- **`internal/handlers/handlers.go`** — Removed `index.html` from the template map (no longer rendered).
- **`internal/handlers/handlers_test.go`** — Replaced the old "handler is not nil" test with two proper redirect tests:
  - `unauthenticated redirects to login` — verifies 303 to `/pages/login`
  - `authenticated redirects to sources` — sets up an authenticated session cookie, verifies 303 to `/sources`
  - Removed `TestFormatUptime` (tested dead code).
- **`README.md`** — Updated the API endpoints table to describe the new redirect behavior.

### How it works

The handler calls `session.Get(r)` and `session.IsAuthenticated(sess)` — the same pattern used by the `RequireAuth` middleware and `HandleLoginPage`. No new dependencies or session logic introduced.

The login flow is unaffected: `HandleLoginSubmit` redirects to `/` after successful login, which now forwards to `/sources` (one extra redirect hop, but correct and clean).

Co-authored-by: clawbot <clawbot@noreply.git.eeqj.de>
Co-authored-by: clawbot <clawbot@eeqj.de>
Reviewed-on: #52
Co-authored-by: clawbot <clawbot@noreply.example.org>
Co-committed-by: clawbot <clawbot@noreply.example.org>

internal/handlers/index.go

@@ -1,49 +1,20 @@
 package handlers
 
 import (
-	"fmt"
 	"net/http"
-	"time"
-
-	"sneak.berlin/go/webhooker/internal/database"
 )
 
+// HandleIndex returns a handler for the root path that redirects based
+// on authentication state: authenticated users go to /sources (the
+// dashboard), unauthenticated users go to the login page.
 func (s *Handlers) HandleIndex() http.HandlerFunc {
-	// Calculate server start time
-	startTime := time.Now()
-
-	return func(w http.ResponseWriter, req *http.Request) {
-		// Calculate uptime
-		uptime := time.Since(startTime)
-		uptimeStr := formatUptime(uptime)
-
-		// Get user count from database
-		var userCount int64
-		s.db.DB().Model(&database.User{}).Count(&userCount)
-
-		// Prepare template data
-		data := map[string]interface{}{
-			"Version":   s.params.Globals.Version,
-			"Uptime":    uptimeStr,
-			"UserCount": userCount,
+	return func(w http.ResponseWriter, r *http.Request) {
+		sess, err := s.session.Get(r)
+		if err == nil && s.session.IsAuthenticated(sess) {
+			http.Redirect(w, r, "/sources", http.StatusSeeOther)
+			return
 		}
 
-		// Render the template
-		s.renderTemplate(w, req, "index.html", data)
+		http.Redirect(w, r, "/pages/login", http.StatusSeeOther)
 	}
 }
-
-// formatUptime formats a duration into a human-readable string
-func formatUptime(d time.Duration) string {
-	days := int(d.Hours()) / 24
-	hours := int(d.Hours()) % 24
-	minutes := int(d.Minutes()) % 60
-
-	if days > 0 {
-		return fmt.Sprintf("%dd %dh %dm", days, hours, minutes)
-	}
-	if hours > 0 {
-		return fmt.Sprintf("%dh %dm", hours, minutes)
-	}
-	return fmt.Sprintf("%dm", minutes)
-}