Implement custom feed favicons (#7646)

Closes #3789, #6503

Icon setting when no custom icon is set yet:

![image](https://github.com/user-attachments/assets/28b07dd0-7dac-4c76-b1d7-77035f91a87a)

- `Change...` button opens a file dialog, and after selecting a file shows the chosen icon in the preview on the left. `Submit` must be clicked after selecting the icon.
- `Reset to default` changes the preview icon to the default one, and also requires `Submit` to be clicked to apply the changes.

Full list of changes:
- CSP now includes `blob:` in `img-src` for
   - `indexAction()` and `feedAction()` in `subscriptionController.php`
   - all of the view actions in `indexController.php`
- Introduce new attribute `customFavicon (boolean)` for feeds that indicates if the feed has a custom favicon
   - `hashFavicon()` in `Feed.php` is dependent on this attribute
      - `hashFavicon()` has a new parameter called `skipCache (boolean)` that allows the reset of the favicon hash for the Feed object
      - `resetFaviconHash()` just calls `hashFavicon(skipCache: true)`
- `f.php` URLs now have the format of `/f.php?h=XXXXX&t=cachebuster`, where the `t` parameter is only used for serving custom favicons
   - if `t` parameter is set, `f.php` returns a `Cache-Control: immutable` header
- `stripos` and `strpos` were changed to `str_contains` in various places (refactor)
- JS for handling the custom favicon configuration logic is in `extra.js` inside `init_update_feed()` which is called when feed configuration is opened from the aside or when the subscription management page with the feed is loaded
   - Server-side code for uploading the icon in `subscriptionController.php` under `feedAction()`
   - Errors that may occur during the setting of a custom favicon:
      - Unsupported image file type (handled only server-side with `isImgMime()`)
      - When the file is bigger than 1 MiB (default), handled both client-side and server-side
      - Standard feed error when `updateFeed()` fails
- JS vars `javascript_vars.phtml` are no longer escaped with `htmlspecialchars()`, instead with json encoding,
- CSS for disabled buttons was added
- Max favicon file size is configurable with the `max_favicon_upload_size` option in `config.php` (not exposed via UI)
- Custom favicons are currently deleted only when they are either reset to the default icon, or the feed gets deleted. They do not get deleted when the user deletes their account without removing their feeds first.
- ` faviconPrepare()` and `faviconRebuild()` are not allowed to be called when the `customFavicon` attribute is `true`
- New i18n strings:
   - `'sub.feed.icon' => 'Icon'`
   - `'sub.feed.change_favicon' => 'Change…'`
   - `'sub.feed.reset_favicon' => 'Reset to default'`
   - `'sub.feed.favicon_changed_by_ext' => 'The icon has been set by the <b>%s</b> extension.'`
   - `'feedback.sub.feed.favicon.too_large' => 'Uploaded icon is too large. The maximum file size is <em>%s</em>.'`
   - `'feedback.sub.feed.favicon.unsupported_format' => 'Unsupported image file format!'`
- Extension hook `custom_favicon_hash`
   - `setCustomFavicon()` method
   - `resetCustomFavicon()` method
   - `customFaviconExt` and `customFaviconDisallowDel` attributes
   - example of usage: https://github.com/FreshRSS/Extensions/pull/337
- Extension hook `custom_favicon_btn_url`
   - Allows extensions to implement a button for setting a custom favicon for individual feeds by providing an URL. The URL will be sent a POST request with the `extAction` field set to either `query_icon_info` or `update_icon`, along with an `id` field which describes the feed's ID.

1 files changed, 5 insertions, 0 deletions

diff --git a/app/i18n/es/sub.php b/app/i18n/es/sub.php
index 0518b6b11..d57bb0a9f 100644
--- a/app/i18n/es/sub.php
+++ b/app/i18n/es/sub.php
@@ -50,6 +50,7 @@ return array(
 			'password' => 'Contraseña HTTP',
 			'username' => 'Nombre de usuario HTTP',
 		),
+		'change_favicon' => 'Change…',	// TODO
 		'clear_cache' => 'Borrar siempre la memoria caché',
 		'content_action' => array(
 			'_' => 'Acción de contenido al obtener el contenido del artículo',
@@ -74,12 +75,15 @@ return array(
 			'help' => 'archivo XML (conjunto de datos. <a href="https://freshrss.github.io/FreshRSS/en/developers/OPML.html" target="_blank">Ver la documentación</a>)',
 			'label' => 'Exportar como OPML',
 		),
+		'ext_favicon' => 'Set automatically',	// TODO
+		'favicon_changed_by_ext' => 'The icon has been set by the <b>%s</b> extension.',	// TODO
 		'filteractions' => array(
 			'_' => 'Filtrar acciones',
 			'help' => 'Escribir un filtro de búsqueda por línea. Ver <a href="https://freshrss.github.io/FreshRSS/en/users/10_filter.html#with-the-search-field" target="_blank">documentación de operadores de búsqueda</a>.',
 		),
 		'http_headers' => 'HTTP Headers',	// IGNORE
 		'http_headers_help' => 'Los Headers son separados por un salto de linea, y el nombre y valor de un Header son separados con dos puntos (e.g: <kbd><code>Accept: application/atom+xml<br />Authorization: Bearer some-token</code></kbd>).',
+		'icon' => 'Icon',	// TODO
 		'information' => 'Información',
 		'keep_min' => 'Número mínimo de artículos a conservar',
 		'kind' => array(
@@ -212,6 +216,7 @@ return array(
 		),
 		'proxy' => 'Establecer un proxy para obtener esta fuente',
 		'proxy_help' => 'Seleccione un protocolo (e.g: SOCKS5) e introduzca la dirección del proxy (e.g: <kbd>127.0.0.1:1080</kbd> o <kbd>username:password@127.0.0.1:1080</kbd>)',
+		'reset_favicon' => 'Reset to default',	// TODO
 		'selector_preview' => array(
 			'show_raw' => 'Mostrar código fuente',
 			'show_rendered' => 'Mostrar contenido',