[mod] client/simple: client plugins (#5406)

* [mod] client/simple: client plugins

Defines a new interface for client side *"plugins"* that coexist with server
side plugin system. Each plugin (e.g., `InfiniteScroll`) extends the base
`ts Plugin`. Client side plugins are independent and lazy‑loaded via `router.ts`
when their `load()` conditions are met. On each navigation request, all
applicable plugins are instanced.

Since these are client side plugins, we can only invoke them once DOM is fully
loaded. E.g. `Calculator` will not render a new `answer` block until fully
loaded and executed.

For some plugins, we might want to handle its availability in `settings.yml`
and toggle in UI, like we do for server side plugins. In that case, we extend
`py Plugin` instancing only the information and then checking client side if
[`settings.plugins`](https://github.com/inetol/searxng/blob/1ad832b1dc33f3f388da361ff2459b05dc86a164/client/simple/src/js/toolkit.ts#L134)
array has the plugin id.

* [mod] client/simple: rebuild static

2 files changed, 7 insertions, 13 deletions

diff --git a/client/simple/src/less/embedded.less b/client/simple/src/less/embedded.less
index 953d4f982..9fcde65b0 100644
--- a/client/simple/src/less/embedded.less
+++ b/client/simple/src/less/embedded.less
@@ -1,19 +1,16 @@
 // SPDX-License-Identifier: AGPL-3.0-or-later
 
-iframe[src^="https://w.soundcloud.com"]
-{
+iframe[src^="https://w.soundcloud.com"] {
   height: 120px;
 }
 
-iframe[src^="https://www.deezer.com"]
-{
+iframe[src^="https://www.deezer.com"] {
   // The real size is 92px, but 94px are needed to avoid an inner scrollbar of
   // the embedded HTML.
   height: 94px;
 }
 
-iframe[src^="https://www.mixcloud.com"]
-{
+iframe[src^="https://www.mixcloud.com"] {
   // the embedded player from mixcloud has some quirks: initial there is an
   // issue with an image URL that is blocked since it is an a Cross-Origin
   // request. The alternative text (<img alt='Mixcloud Logo'> then cause an
@@ -23,19 +20,16 @@ iframe[src^="https://www.mixcloud.com"]
   height: 250px;
 }
 
-iframe[src^="https://bandcamp.com/EmbeddedPlayer"]
-{
+iframe[src^="https://bandcamp.com/EmbeddedPlayer"] {
   // show playlist
   height: 350px;
 }
 
-iframe[src^="https://bandcamp.com/EmbeddedPlayer/track"]
-{
+iframe[src^="https://bandcamp.com/EmbeddedPlayer/track"] {
   // hide playlist
   height: 120px;
 }
 
-iframe[src^="https://genius.com/songs"]
-{
+iframe[src^="https://genius.com/songs"] {
   height: 65px;
 }
diff --git a/client/simple/src/less/index.less b/client/simple/src/less/index.less
index c96b0f706..6d9e4abd4 100644
--- a/client/simple/src/less/index.less
+++ b/client/simple/src/less/index.less
@@ -8,7 +8,7 @@
   text-align: center;
 
   .title {
-    background: url("../img/searxng.png") no-repeat;
+    background: url("./img/searxng.png") no-repeat;
     min-height: 4rem;
     margin: 4rem auto;
     background-position: center;