feat(tower): cap shows at latest N per feed

The additive refresh accumulated episodes without bound (Oli reached 13).
Tag each manifest episode with a source (auto/pick/upload); the refresh now
prunes "auto" episodes that aged out of the feed's latest N while keeping
hand-picked and uploaded ones. Feeds default to N=5.

tower/lisael_content.py

@@ -139,7 +139,9 @@ def manifest_load():
 def manifest_save(m):
     _atomic_write_json(os.path.join(STAGING, "manifest.json"), m)
 
-def _manifest_upsert(m, show, cover, file, title):
+def _manifest_upsert(m, show, cover, file, title, src="auto"):
+    # src: "auto" (weekly refresh), "pick" (hand-selected), "upload" (custom file).
+    # Only "auto" episodes are eligible for pruning by the cap.
     for s in m:
         if s["show"] == show:
             if cover and not s.get("cover"):
@@ -147,14 +149,17 @@ def _manifest_upsert(m, show, cover, file, title):
             for e in s["episodes"]:
                 if e["file"] == file:
                     e["title"] = title
+                    if src != "auto":      # a manual pick/upload wins over auto
+                        e["src"] = src
                     return
-            s["episodes"].append({"file": file, "title": title})
+            s["episodes"].append({"file": file, "title": title, "src": src})
             return
-    m.append({"show": show, "cover": cover or "", "episodes": [{"file": file, "title": title}]})
+    m.append({"show": show, "cover": cover or "",
+              "episodes": [{"file": file, "title": title, "src": src}]})
 
-def add_episode(key, show, cover_bytes, url, title):
+def add_episode(key, show, cover_bytes, url, title, src="auto"):
     """Download + transcode an episode into STAGING + upsert manifest. Idempotent by fname.
-    cover_bytes: raw image bytes for the show cover, or None."""
+    cover_bytes: raw image bytes for the show cover, or None. src: auto|pick."""
     os.makedirs(STAGING, exist_ok=True)
     fname = episode_fname(key, url)
     out = os.path.join(STAGING, fname)
@@ -167,7 +172,7 @@ def add_episode(key, show, cover_bytes, url, title):
             os.replace(tmp_out, out)
     cover = make_cover(cover_bytes, key) if cover_bytes else ""
     m = manifest_load()
-    _manifest_upsert(m, show, cover, fname, clean(title))
+    _manifest_upsert(m, show, cover, fname, clean(title), src)
     manifest_save(m)
     return fname
 
@@ -183,10 +188,33 @@ def add_upload(show, src_bytes, title, key="perso"):
             raise RuntimeError("transcode failed")
         os.replace(tmp_out, out)
     m = manifest_load()
-    _manifest_upsert(m, show, "", fname, clean(title))
+    _manifest_upsert(m, show, "", fname, clean(title), "upload")
     manifest_save(m)
     return fname
 
+def prune_show(show, keep_files):
+    """Cap a feed show: drop its 'auto' episodes whose file is not in keep_files
+    (the current latest-N from the feed). 'pick'/'upload' episodes are always kept.
+    Deletes the staged file too. Returns the number removed."""
+    m = manifest_load()
+    removed = 0
+    for s in m:
+        if s["show"] != show:
+            continue
+        kept = []
+        for e in s["episodes"]:
+            if e.get("src", "auto") != "auto" or e["file"] in keep_files:
+                kept.append(e)
+            else:
+                p = os.path.join(STAGING, e["file"])
+                if os.path.exists(p):
+                    os.remove(p)
+                removed += 1
+        s["episodes"] = kept
+    m = [s for s in m if s["episodes"]]
+    manifest_save(m)
+    return removed
+
 def remove_file(name):
     if "/" in name or ".." in name or name.startswith("."):
         raise ValueError("bad name")

tower/lisael_refresh.py

@@ -1,12 +1,13 @@
 #!/usr/bin/env python3
-"""Weekly refresh: for each configured feed, add the latest N missing episodes to
-the staging set. ADDITIVE — never wipes manual selections or uploads."""
+"""Weekly refresh: for each configured feed, keep the latest N episodes staged.
+Adds the new ones (src=auto) and prunes auto episodes that aged out of the feed's
+latest N. Hand-picked ('pick') and uploaded ('upload') episodes are never touched."""
 import lisael_content as C
 
 def main():
-    added = 0
+    added = removed = 0
     for fd in C.load_feeds():
-        key, show, rss, n = fd["key"], fd["name"], fd["rss"], int(fd.get("n", 2))
+        key, show, rss, n = fd["key"], fd["name"], fd["rss"], int(fd.get("n", 5))
         try:
             eps, cov = C.fetch_episodes(rss, limit=n)
         except Exception as e:
@@ -18,17 +19,22 @@ def main():
             except Exception:
                 cover_bytes = None
         staged = set(C.staging_files())
+        want = set()
         for ep in eps:
-            if C.episode_fname(key, ep["url"]) in staged:
+            fn = C.episode_fname(key, ep["url"])
+            want.add(fn)
+            if fn in staged:
                 continue
             try:
                 C.add_episode(key, show, cover_bytes, ep["url"], ep["title"])
                 cover_bytes = None  # cover only needs writing once per show
                 added += 1
-                print("added", C.episode_fname(key, ep["url"]), flush=True)
+                print("added", fn, flush=True)
             except Exception as e:
                 print("add fail", key, e, flush=True)
-    print(f"refresh done: +{added} episodes, {len(C.staging_files())} files", flush=True)
+        # Cap: drop auto episodes that are no longer in the feed's latest N.
+        removed += C.prune_show(show, want)
+    print(f"refresh done: +{added} -{removed}, {len(C.staging_files())} files", flush=True)
 
 if __name__ == "__main__":
     main()

tower/lisael_server.py

@@ -138,7 +138,7 @@ class H(BaseHTTPRequestHandler):
                     cover_bytes = None
                 for ep in episodes:
                     try:
-                        C.add_episode(key, feed["name"], cover_bytes, ep["url"], ep.get("title", ""))
+                        C.add_episode(key, feed["name"], cover_bytes, ep["url"], ep.get("title", ""), src="pick")
                         cover_bytes = None
                         print("selected", C.episode_fname(key, ep["url"]), flush=True)
                     except Exception as e:

tower/test_content.py

@@ -41,6 +41,25 @@ def test_bad_name_rejected():
     except ValueError:
         pass
 
+def test_prune_show_caps_auto_keeps_manual():
+    os.makedirs(C.STAGING, exist_ok=True)
+    m = []
+    # 2 auto (one stays, one ages out) + 1 hand-picked old + 1 upload
+    C._manifest_upsert(m, "Sh", "sh.bin", "sh_new_a48.mp3", "new", "auto")
+    C._manifest_upsert(m, "Sh", "", "sh_old_a48.mp3", "old", "auto")
+    C._manifest_upsert(m, "Sh", "", "sh_pick_a48.mp3", "picked", "pick")
+    C._manifest_upsert(m, "Sh", "", "sh_up_a48.mp3", "uploaded", "upload")
+    C.manifest_save(m)
+    for f in ("sh_new_a48.mp3", "sh_old_a48.mp3", "sh_pick_a48.mp3", "sh_up_a48.mp3"):
+        open(os.path.join(C.STAGING, f), "wb").close()
+    # keep only the new auto episode; old auto should be pruned, manual kept
+    removed = C.prune_show("Sh", {"sh_new_a48.mp3"})
+    assert removed == 1
+    files = {e["file"] for e in C.manifest_load()[0]["episodes"]}
+    assert files == {"sh_new_a48.mp3", "sh_pick_a48.mp3", "sh_up_a48.mp3"}
+    assert not os.path.exists(os.path.join(C.STAGING, "sh_old_a48.mp3"))
+    assert os.path.exists(os.path.join(C.STAGING, "sh_pick_a48.mp3"))
+
 if __name__ == "__main__":
     for name, fn in sorted(globals().items()):
         if name.startswith("test_"):