fix(player): marks give way to newer lists, Watch later items mark, and auto-advance has its own glyphs

A session's marks are weighed per field against when each page of a never-refetched list was read:
a page read before the mark (a Show more / Load more on its way) takes it, one read after keeps the
server's word. The live search lays them over its rows too, not only the related list.

Items of the built-in Watch later list ARE the bookmark, so adding, removing and moving them go
through features/video/videoWrites and mark the video; the contract test covers those writes and
catches a write that is named without being called on the spot.

The player's watched toggle follows a mark confirmed elsewhere since it opened (the related row's
menu, a notice's Undo); Restart on the related row after a description link goes back to it.
The file viewer tells the help sheet its keys wait under a layer; refusalReason replaces the last
two open-coded reads.

Auto-advance wears list glyphs of its own (the skip arrows are Previous / Next beside it), and the
auto-advance and loop cycles are `lit`, not toggles: no aria-pressed, the name says the mode. Both
places render from one list of controls, so the docked tooltips name the mode too. The English cap
message and admin hint quote "Show more"; the hint says refunds are limited.

frontend/src/i18n/locales/en/config.json

@@ -56,7 +56,7 @@
     },
     "related_daily_limit_per_user": {
       "label": "Related videos — daily limit per user",
-      "hint": "Max related-video requests a user can make per day — opening a list and each Show more count one. They come from YouTube's website and spend no search quota; looking up the videos in one costs up to about 8 units (up to 4 pages, each a video and a channel lookup). A failed one doesn't count. Set 0 to turn related videos off."
+      "hint": "Max related-video requests a user can make per day — opening a list counts one, and so does every “Show more”. They come from YouTube's website and spend no search quota; looking up the videos in one costs up to about 8 units (up to 4 pages, each a video and a channel lookup). A failed one doesn't count (up to 5 an hour). Set 0 to turn related videos off."
     },
     "search_daily_limit_per_user": {
       "label": "Live search — daily limit per user",

frontend/src/i18n/locales/en/errors.json

@@ -189,7 +189,7 @@
     "recipient_required": "A recipient email is required",
     "registration_closed": "Registration is currently closed",
     "related_disabled": "Related videos are turned off on this instance.",
-    "related_daily_limit": "You've reached today's related videos limit ({{limit}}). Opening a list and each Show more count as one request. Try again tomorrow.",
+    "related_daily_limit": "You've reached today's related videos limit ({{limit}}). Opening a list counts as one request, and so does every “Show more”. Try again tomorrow.",
     "search_disabled": "Live YouTube search is turned off on this instance.",
     "search_daily_limit": "You've reached today's YouTube search limit ({{limit}}). Try again tomorrow.",
     "search_term_required": "Enter something to search for",

frontend/src/i18n/locales/hu/config.json

@@ -56,7 +56,7 @@
     },
     "related_daily_limit_per_user": {
       "label": "Kapcsolódó videók — napi limit / felhasználó",
-      "hint": "Hányszor kérhet kapcsolódó videókat egy felhasználó naponta — egy lista megnyitása és minden „Mutass többet” egynek számít. A YouTube weboldaláról jönnek, keresési kvótát nem fogyasztanak; a bennük lévő videók lekérése kérésenként legfeljebb kb. 8 egység (legfeljebb 4 oldal, mindegyik egy videó- és egy csatornalekérés). A sikertelen nem számít. 0 = a kapcsolódó videók kikapcsolva."
+      "hint": "Hányszor kérhet kapcsolódó videókat egy felhasználó naponta — egy lista megnyitása és minden „Mutass többet” egynek számít. A YouTube weboldaláról jönnek, keresési kvótát nem fogyasztanak; a bennük lévő videók lekérése kérésenként legfeljebb kb. 8 egység (legfeljebb 4 oldal, mindegyik egy videó- és egy csatornalekérés). A sikertelen nem számít (óránként legfeljebb 5). 0 = a kapcsolódó videók kikapcsolva."
     },
     "search_daily_limit_per_user": {
       "label": "Élő keresés — napi limit / felhasználó",