Replace onclick navigation with proper links

Converts cancel buttons that use onclick="window.location.href='...'" to
proper A tags with href. This improves accessibility (keyboard navigation,
right-click options) and semantics while maintaining the same button styling.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

src/animaltrack/web/templates/actions.py

@@ -4,7 +4,7 @@
 from collections.abc import Callable
 from typing import Any
 
-from fasthtml.common import H2, H3, Div, Form, Hidden, Input, Option, P, Script, Select, Span
+from fasthtml.common import H2, H3, A, Div, Form, Hidden, Input, Option, P, Script, Select, Span
 from monsterui.all import (
     Alert,
     AlertT,
@@ -86,11 +86,10 @@ def diff_confirmation_panel(
         Hidden(name="confirmed", value="true"),
         Hidden(name="nonce", value=str(ULID())),
         Div(
-            Button(
+            A(
                 "Cancel",
-                type="button",
+                href=cancel_url,
                 cls=ButtonT.default,
-                onclick=f"window.location.href='{cancel_url}'",
             ),
             Button(
                 confirm_button_text,

src/animaltrack/web/templates/move.py

@@ -4,7 +4,7 @@
 from collections.abc import Callable
 from typing import Any
 
-from fasthtml.common import H2, Div, Form, Hidden, Option, P, Select, Span
+from fasthtml.common import H2, A, Div, Form, Hidden, Option, P, Select, Span
 from monsterui.all import Alert, AlertT, Button, ButtonT, FormLabel, LabelInput, LabelTextArea
 from ulid import ULID
 
@@ -253,11 +253,10 @@ def diff_panel(
         Hidden(name="confirmed", value="true"),
         Hidden(name="nonce", value=str(ULID())),
         Div(
-            Button(
+            A(
                 "Cancel",
-                type="button",
+                href="/move",
                 cls=ButtonT.default,
-                onclick="window.location.href='/move'",
             ),
             Button(
                 f"Confirm Move ({diff.server_count} animals)",