posts: eliminate pool_id, favgroup_id url params.

Replace the `pool_id` and `favgroup_id` url params:

    https://danbooru.donmai.us/posts/123?pool_id=456
    https://danbooru.donmai.us/posts/123?favgroup_id=456

with the `q` param:

    https://danbooru.donmai.us/posts/123?q=pool:456
    https://danbooru.donmai.us/posts/123?q=favgroup:456

test/components/post_navbar_component_test.rb

@@ -20,33 +20,51 @@ class PostNavbarComponentTest < ViewComponent::TestCase
     end
 
     context "for a post with pools" do
-      should "render" do
+      setup do
         as(@user) do
           @pool1 = create(:pool, category: "series")
           @pool2 = create(:pool, category: "collection")
           @post.update(tag_string: "pool:#{@pool1.id} pool:#{@pool2.id}")
         end
+      end
 
-        render_post_navbar(@post, current_user: @user, pool_id: @pool1.id)
+      should "render" do
+        render_post_navbar(@post, current_user: @user)
 
         assert_css(".pool-name", text: "Pool: #{@pool1.pretty_name}")
         assert_css(".pool-name", text: "Pool: #{@pool2.pretty_name}")
       end
+
+      should "highlight the selected pool" do
+        render_post_navbar(@post, current_user: @user, search: "pool:#{@pool1.id}")
+
+        assert_css(".pool-navbar[data-selected=true] .pool-name", text: "Pool: #{@pool1.pretty_name}")
+        assert_css(".pool-navbar[data-selected=false] .pool-name", text: "Pool: #{@pool2.pretty_name}")
+      end
     end
 
     context "for a post with favgroups" do
-      should "render" do
+      setup do
         as(@user) do
           @favgroup1 = create(:favorite_group, creator: @user)
           @favgroup2 = create(:favorite_group, creator: @user)
           @post.update(tag_string: "favgroup:#{@favgroup1.id} favgroup:#{@favgroup2.id}")
         end
+      end
 
-        render_post_navbar(@post, current_user: @user, favgroup_id: @favgroup1.id)
+      should "render" do
+        render_post_navbar(@post, current_user: @user, search: "favgroup:#{@favgroup1.id}")
 
         assert_css(".favgroup-name", text: "Favgroup: #{@favgroup1.pretty_name}")
         assert_css(".favgroup-name", text: "Favgroup: #{@favgroup2.pretty_name}")
       end
+
+      should "highlight the selected favgroup" do
+        render_post_navbar(@post, current_user: @user, search: "favgroup:#{@favgroup1.id}")
+
+        assert_css(".favgroup-navbar[data-selected=true] .favgroup-name", text: "Favgroup: #{@favgroup1.pretty_name}")
+        assert_css(".favgroup-navbar[data-selected=false] .favgroup-name", text: "Favgroup: #{@favgroup2.pretty_name}")
+      end
     end
   end
 end