feat: what you pay for, against what FC actually follows (387 C4)

Reconciliation in Subscriptions, asymmetric on purpose. Subscriptions FC does not follow get a per-row add; sources the roster cannot account for are REPORT ONLY (operator decision) and link to the list on the same page. No one-click disable, so no disabled-reason column and no migration.

The membership<->source join lands as a SHARED resolver in membership_roster, not inline here: E4 now uses it as its negative check, so the two features cannot give different answers to 'is this membership already tracked?'. Keys on the exact cached campaign id FIRST and the URL handle only as fallback, because the id is written only after a source has been walked once. Read via any <platform>_campaign_id override rather than naming Patreon's, per rule 169.

The report-only bucket is gated on roster freshness and carries a per-row basis, so 'your membership says former patron', 'we know this id and it is absent', and 'we only have a handle' stay three different sentences. has_paid_access None never reads as lapsed.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01LNXXULQDjVZmbuNa2G9mD9

backend/app/api/sources.py

@@ -7,7 +7,9 @@ from ..extensions import get_session
 from ..models import DownloadEvent, MembershipSync, PlatformMembership, Source
 from ..services.artist_membership_service import ArtistMembershipService
 from ..services.artist_membership_service import rescan as membership_rescan
-from ..services.membership_roster import roster_is_fresh
+from ..services.artist_service import ArtistService
+from ..services.membership_reconcile import reconcile_all
+from ..services.membership_roster import roster_is_fresh, source_for_membership
 from ..services.scheduler_service import active_platform_cooldowns, scheduler_status
 from ..services.source_service import (
     KNOWN_PLATFORMS,
@@ -386,3 +388,68 @@ async def rescan_membership_suggestions():
         result = await membership_rescan(session)
         await session.commit()
     return jsonify(result)
+
+
+# --- #387 C4: reconciling the roster against what FC actually tracks -------
+#
+# Asymmetric on purpose. The "you subscribe but FC doesn't follow it" direction
+# carries a per-row action, because adding a source is the reversible half. The
+# "FC follows it but your roster doesn't show it" direction is REPORT ONLY by
+# the operator's decision (2026-09-11): it says what it sees and links to the
+# Subscriptions row, and offers no one-click disable.
+
+
+@sources_bp.route("/reconciliation", methods=["GET"])
+async def reconciliation():
+    async with get_session() as session:
+        return jsonify(await reconcile_all(session))
+
+
+@sources_bp.route("/reconciliation/adopt", methods=["POST"])
+async def adopt_membership():
+    """Start tracking a creator the roster says the account already pays for.
+
+    One row, one click, never a sweep side effect: adding a source commits disk,
+    worker time and rate budget, and unwinding it means deleting files.
+    """
+    body = await request.get_json()
+    if not isinstance(body, dict):
+        return _bad("invalid_body", status=400)
+    membership_id = body.get("membership_id")
+    if not isinstance(membership_id, int):
+        return _bad("membership_id_required", status=400)
+
+    async with get_session() as session:
+        membership = await session.get(PlatformMembership, membership_id)
+        if membership is None:
+            return _bad("membership_not_found", status=404)
+        if not membership.url:
+            return _bad("membership_has_no_url", status=400)
+
+        existing = await source_for_membership(session, membership)
+        if existing is not None:
+            # The operator got there by another route between the page load and
+            # the click. That is them being ahead of us, not an error.
+            return jsonify({"already_tracked": existing.id})
+
+        # The sweep already captured the creator's real display name, so the
+        # artist gets its true name with NO lookup on the request path. Task
+        # #1293 asked for `resolve_display_name` here; the roster satisfies that
+        # concern earlier in the pipeline than #1293 expected, which also keeps
+        # this route off the network entirely (rule 164). The vanity is the
+        # fallback, never the preferred value.
+        name = membership.display_name or membership.vanity_or_none()
+        if not name:
+            return _bad("membership_has_no_name", status=400)
+
+        artist, _created = await ArtistService(session).find_or_create(name)
+        try:
+            record = await SourceService(session).create(
+                artist_id=artist.id,
+                platform=membership.platform,
+                url=membership.url,
+            )
+        except DuplicateSourceError as exc:
+            return jsonify({"already_tracked": exc.existing_id})
+        artist_id = artist.id
+    return jsonify({"source_id": record.id, "artist_id": artist_id}), 201