"Since you last visited" cue + PWA install (add to home screen)

Two calm returning-reader features.

Since-last-visit (Highlights companion, not a nav lane — per Codex):
* queries.feed gains a `since` filter; GET /api/since?ts= returns the count +
  a few accepted/non-dup/visible articles discovered since the reader's last
  visit (boundary-respecting; invalid/future ts → 0, no error).
* Home stores last_seen in localStorage (reads prev, then stamps now); on
  Highlights, a gentle "Since you were last here, N new calm reads came in"
  note with a "See what's new" reveal of a compact inline section. Dismissible.
  No badges, no unread counts, no "missed" language.

PWA:
* Real PNG icons (192/512 + full-bleed maskable) rasterized from favicon.svg;
  manifest fixed (azure theme to match the brand, PNG icons); apple-touch-icon.
* Minimal service worker: precache the app shell, always-fresh API + /a/ pages.
* Gentle, dismissible install banner (beforeinstallprompt → Install; iOS → the
  Share → Add to Home Screen hint). Never nags.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

goodnews/api.py

@@ -1422,6 +1422,27 @@ def create_app() -> FastAPI:
             items=[Article.from_row(r) for r in rows],
         )
 
+    @app.get("/api/since", response_model=FeedResponse)
+    def feed_since(ts: str = Query(...), prefs: str | None = Query(None)) -> FeedResponse:
+        # A calm welcome-back cue: accepted/non-dup/visible articles discovered
+        # since the reader's last visit (boundary-respecting). count = how many;
+        # items = a few to show inline. No nagging, no unread state stored.
+        try:
+            norm = ts.replace("Z", "+00:00")
+            dt = datetime.fromisoformat(norm)
+            since = (dt.astimezone(timezone.utc) if dt.tzinfo else dt).strftime("%Y-%m-%d %H:%M:%S")
+        except (ValueError, TypeError):
+            return FeedResponse(topic=None, flavor=None, count=0, items=[])
+        fp = prefs_from_json(prefs)
+        now = datetime.now(timezone.utc)
+        kw = _prefs_sql_kw(fp, now)
+        with get_conn() as conn:
+            rows = queries.feed(conn, sort="latest", since=since, limit=60, **kw)
+        if fp.avoid_terms:
+            rows = filter_articles(rows, fp, now)
+        rows = sorted(rows, key=lambda r: is_paywalled(r["canonical_url"]))
+        return FeedResponse(topic=None, flavor=None, count=len(rows), items=[Article.from_row(r) for r in rows[:8]])
+
     @app.get("/api/brief", response_model=BriefResponse)
     def brief(
         date: str | None = Query(None),

goodnews/queries.py

@@ -64,6 +64,7 @@ def feed(
     sort: str = "ranked",
     follow_sources: list[int] | None = None,
     follow_tags: list[str] | None = None,
+    since: str | None = None,
 ) -> list[dict]:
     """Return articles with categorical filters applied in SQL.
 
@@ -116,6 +117,11 @@ def feed(
         clauses.append("a.source_id = ?")
         params.append(source_id)
 
+    if since:
+        # "New since last visit": articles discovered after the reader's last visit.
+        clauses.append("a.discovered_at > ?")
+        params.append(since)
+
     # "Following" feed: articles from a followed source OR carrying a followed tag.
     # Passing either list (even empty) switches to following mode; no follows → none.
     if follow_sources is not None or follow_tags is not None: