webui: improve/simplify commit selector in Monaco diff view

The HTML select's cant be formatted to show tags nicely, so
did a "custom" select thing.

Furthermore, I never use the "to" thing, so let's just get rid of
it, and we're always going from someplace to someplace.

I don't love the overflow behavior, but we'll see how it goes.

Co-Authored-By: sketch <hello@sketch.dev>
Change-ID: s9f70e9aef1fb08c4k
diff --git a/webui/src/web-components/demo/mock-git-data-service.ts b/webui/src/web-components/demo/mock-git-data-service.ts
index 894d9aa..046d9ec 100644
--- a/webui/src/web-components/demo/mock-git-data-service.ts
+++ b/webui/src/web-components/demo/mock-git-data-service.ts
@@ -17,17 +17,21 @@
     {
       hash: "abc123456789",
       subject: "Implement new file picker UI",
-      refs: ["HEAD", "main"],
+      refs: ["HEAD", "origin/main", "refs/heads/feature/file-picker"],
     },
     {
       hash: "def987654321",
-      subject: "Add range picker component",
-      refs: [],
+      subject: "Add range picker component and improve styling",
+      refs: [
+        "origin/feature/range-picker",
+        "refs/heads/feature/ui-improvements",
+        "refs/remotes/origin/dev",
+      ],
     },
     {
       hash: "ghi456789123",
-      subject: "Fix styling issues in navigation",
-      refs: [],
+      subject: "Fix styling issues in navigation and add responsive design",
+      refs: ["refs/heads/hotfix/styling", "refs/tags/v1.2.0"],
     },
     {
       hash: "jkl789123456",