Redirect legacy page names to the new routes (v0.9.4)

The retired legacy instance now blanket-redirects its old host to the new
one, so pre-rewrite deep links like /index.html or /branches.html arrive
here — they answer 301 to the new routes instead of 404; about/license had
no successor pages and land on the start page.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

src/test/kotlin/de/hoennig/gittally/server/UiControllerTest.kt

@@ -28,6 +28,7 @@ import org.springframework.http.HttpStatus
 import org.springframework.test.web.servlet.MockMvc
 import org.springframework.test.web.servlet.request.MockMvcRequestBuilders.get
 import org.springframework.test.web.servlet.result.MockMvcResultMatchers.content
+import org.springframework.test.web.servlet.result.MockMvcResultMatchers.header
 import org.springframework.test.web.servlet.result.MockMvcResultMatchers.status
 import org.springframework.web.server.ResponseStatusException
 import java.nio.file.Files
@@ -270,6 +271,21 @@ class UiControllerTest : FunSpec() {
             Regex(""" failed</span>""").findAll(page).count() shouldBe 1
         }
 
+        test("legacy page names redirect permanently to the new routes") {
+            mockMvc
+                .perform(get("/index.html"))
+                .andExpect(status().isMovedPermanently)
+                .andExpect(header().string("Location", "/"))
+            mockMvc
+                .perform(get("/branches.html"))
+                .andExpect(status().isMovedPermanently)
+                .andExpect(header().string("Location", "/branches"))
+            mockMvc
+                .perform(get("/history.html"))
+                .andExpect(status().isMovedPermanently)
+                .andExpect(header().string("Location", "/history"))
+        }
+
         test("artifact index of a pruned build explains the missing artifacts") {
             every { repository.history() } returns listOf(successResult)
             every { artifactStore.artifactDir("main-abc123-key") } returns null