docs/podcasts.md: Podcast-Radio geplant (neueste ungehörte Strom-Folge, keine Spuren, eigene Radio-gehört-Liste)

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

docs/podcasts.md

@@ -92,6 +92,32 @@ One controlled step out (Apple's episode search and fyyd; no key):
 
 Show search stays on Apple (best coverage).
 
+## Podcast-Radio (planned 2026-10-25)
+
+Listening without committing: one button plays the Strom like a station.
+
+- **The rule**: the radio always plays the **newest** (publication date) Strom episode that is
+  neither played, nor started (normally), nor done for the radio. So an episode that comes out
+  while one plays is next (the one playing isn't interrupted); otherwise it goes back in time,
+  without limit. Auf Abruf podcasts and audiobooks aren't in the Strom, so not in the radio.
+- **Leaves no trace**: no progress (no Verlauf, no "Angefangen", no played mark, not counted in
+  `heard_365`), the Wiedergabeliste and Merkliste unchanged, nothing downloaded (it streams; a
+  downloaded file plays if there is one), the Strom's marks unchanged.
+- **Done for the radio**: run to its end or skipped (⏭, notification, headset, car). Pausing
+  isn't: the radio keeps its episode and place for itself, ▶ goes on there.
+- **Committing**: in the player while the radio plays, ＋ (Merkliste) and "Normal weiterhören"
+  (first in the Wiedergabeliste at the current place; from then on it plays as usual, with
+  progress). Playing anything normally switches the radio off (as an audiobook does).
+- **Server**: `PodcastRadioHeard(user, episode, at)`, kept apart from progress, pruned after 60
+  days. `GET /podcasts/radio/?limit=5` → the next episodes by the rule (`{episodes: [...]}`, the
+  rows of the episode lists); `POST /podcasts/radio/heard/ {"episode_id"}`. Shared by all devices.
+- **Clients** (both at once): Android (`PodcastRadio.kt` beside `BookPlay.kt`: the playlist is
+  [current, next]; RadioService's `save()` / `markPlayed()` / `followQueue()` leave radio items
+  alone; reloads before each transition and every 10 minutes while playing — the server fetches
+  feeds every 15 minutes) and the web player (`podcasts-web.js`, so the browser and the desktop
+  app). Button "📻 Radio" at the top of the Strom; the mini player's ▶ goes on with the radio.
+- Later perhaps: a radio of one folder, a longest length.
+
 ## Moving over
 
 - Today's queue (74) becomes the Merkliste; the Wiedergabeliste starts empty.