fix watchlist remove (was undone by auto-populate); add watch toggle on ticker page

Removing a ticker did nothing because get_watchlist re-runs auto_populate on
every read, instantly re-adding any top-ranked ticker the user had just removed.
Removals are now tombstoned as a "dismissed" entry_type: auto-population skips
them, the list hides them, and a later manual add revives the row. Also exposes
an Add/Remove-watchlist toggle in the ticker detail header.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

app/services/watchlist_service.py

@@ -26,6 +26,11 @@ logger = logging.getLogger(__name__)
 DEFAULT_AUTO_SIZE = 10
 MAX_MANUAL = 10
 
+# entry_type values. "dismissed" is a tombstone: the user removed the ticker, so
+# auto-population must not silently re-add it on the next read. Dismissed rows are
+# hidden from the watchlist and revived (→ manual) if the user adds them again.
+DISMISSED = "dismissed"
+
 
 async def _get_ticker(db: AsyncSession, symbol: str) -> Ticker:
     normalised = symbol.strip().upper()
@@ -64,19 +69,20 @@ async def auto_populate(
         )
     )
 
-    # Get manual ticker_ids so we don't duplicate
-    manual_result = await db.execute(
+    # Get manual + dismissed ticker_ids so we don't duplicate or resurrect a
+    # ticker the user has explicitly removed.
+    kept_result = await db.execute(
         select(WatchlistEntry.ticker_id).where(
             WatchlistEntry.user_id == user_id,
-            WatchlistEntry.entry_type == "manual",
+            WatchlistEntry.entry_type.in_(["manual", DISMISSED]),
         )
     )
-    manual_ticker_ids = {row[0] for row in manual_result.all()}
+    excluded_ticker_ids = {row[0] for row in kept_result.all()}
 
     now = datetime.now(timezone.utc)
     for ticker_id in top_ticker_ids:
-        if ticker_id in manual_ticker_ids:
-            continue  # Already on watchlist as manual
+        if ticker_id in excluded_ticker_ids:
+            continue  # Already manual, or dismissed by the user
         entry = WatchlistEntry(
             user_id=user_id,
             ticker_id=ticker_id,
@@ -100,17 +106,19 @@ async def add_manual_entry(
     """
     ticker = await _get_ticker(db, symbol)
 
-    # Check if already on watchlist
+    # Check if already on watchlist. A dismissed row is revived as manual rather
+    # than rejected; an active (auto/manual) row is a genuine duplicate.
     existing = await db.execute(
         select(WatchlistEntry).where(
             WatchlistEntry.user_id == user_id,
             WatchlistEntry.ticker_id == ticker.id,
         )
     )
-    if existing.scalar_one_or_none() is not None:
+    existing_entry = existing.scalar_one_or_none()
+    if existing_entry is not None and existing_entry.entry_type != DISMISSED:
         raise DuplicateError(f"Ticker already on watchlist: {ticker.symbol}")
 
-    # Count current manual entries
+    # Count current manual entries (dismissed tombstones don't count)
     count_result = await db.execute(
         select(func.count()).select_from(WatchlistEntry).where(
             WatchlistEntry.user_id == user_id,
@@ -125,10 +133,11 @@ async def add_manual_entry(
             "Remove an entry before adding a new one."
         )
 
-    # Check total cap
+    # Check total cap (exclude dismissed tombstones)
     total_result = await db.execute(
         select(func.count()).select_from(WatchlistEntry).where(
             WatchlistEntry.user_id == user_id,
+            WatchlistEntry.entry_type != DISMISSED,
         )
     )
     total_count = total_result.scalar() or 0
@@ -140,6 +149,14 @@ async def add_manual_entry(
             "Remove an entry before adding a new one."
         )
 
+    if existing_entry is not None:
+        # Revive a dismissed entry as manual.
+        existing_entry.entry_type = "manual"
+        existing_entry.added_at = datetime.now(timezone.utc)
+        await db.commit()
+        await db.refresh(existing_entry)
+        return existing_entry
+
     entry = WatchlistEntry(
         user_id=user_id,
         ticker_id=ticker.id,
@@ -157,20 +174,26 @@ async def remove_entry(
     user_id: int,
     symbol: str,
 ) -> None:
-    """Remove a watchlist entry (manual or auto)."""
+    """Remove a watchlist entry (manual or auto).
+
+    Marks the entry as dismissed (a tombstone) rather than deleting it, so the
+    next auto-population pass won't immediately re-add a top-ranked ticker the
+    user just removed. A subsequent manual add revives the row.
+    """
     ticker = await _get_ticker(db, symbol)
 
     result = await db.execute(
         select(WatchlistEntry).where(
             WatchlistEntry.user_id == user_id,
             WatchlistEntry.ticker_id == ticker.id,
+            WatchlistEntry.entry_type != DISMISSED,
         )
     )
     entry = result.scalar_one_or_none()
     if entry is None:
         raise NotFoundError(f"Ticker not on watchlist: {ticker.symbol}")
 
-    await db.delete(entry)
+    entry.entry_type = DISMISSED
     await db.commit()
 
 
@@ -254,7 +277,10 @@ async def get_watchlist(
     stmt = (
         select(WatchlistEntry, Ticker.symbol)
         .join(Ticker, WatchlistEntry.ticker_id == Ticker.id)
-        .where(WatchlistEntry.user_id == user_id)
+        .where(
+            WatchlistEntry.user_id == user_id,
+            WatchlistEntry.entry_type != DISMISSED,
+        )
     )
     result = await db.execute(stmt)
     rows = result.all()