fix: missing-dep [add] button respects MOD_ID_ALIASES on build mismatch

When user is on B42 and a mod requires the B41 mod_id (e.g.
truemusic_mixtape_megapack require=truemusic), the canonical wsid
(2613146550, B41-only) is rightly filtered out by the build guard —
but we were silently dropping the suggestion. Now we fall back to
MOD_ID_ALIASES: truemusic → TrueMoozic, suggest wsid 3632610172.

- _lookup_wsids_for_missing returns Dict[str, Tuple[wsid, suggested_mod_id]]
- build_warnings unpacks tuple, label clarifies rename when alias used
- adapters.build_response signature updated for new shape

api/adapters.py

@@ -84,17 +84,20 @@ def _resolve_satisfied_via_alias(input_modids: Set[str]) -> Set[str]:
 
 def build_warnings(
     mlos_warnings: Dict[str, Any],
-    wsid_lookup: Dict[str, str] | None = None,
+    wsid_lookup: Dict[str, Tuple[str, str]] | None = None,
     source_wsids: Dict[str, str] | None = None,
     input_modids: Set[str] | None = None,
 ) -> List[Dict[str, Any]]:
     """Translate mlos_sort warnings to the SORTOF_DATA WARNINGS shape.
 
-    wsid_lookup: optional {mod_id -> workshop_id} map of *deps* we already
-    have cached. When provided, each 'missing' warning is augmented with
-    `actions: [{type: "add-wsid", wsid, label}]` so the frontend can render
-    a click-to-add button. Unknown deps fall back to a Steam Workshop search
-    link the user follows manually.
+    wsid_lookup: optional {missing_mod_id -> (workshop_id, suggested_mod_id)}
+    map produced by app._lookup_wsids_for_missing. The `suggested_mod_id`
+    differs from the missing mod_id when a MOD_ID_ALIASES alternative was
+    used because the canonical mod_id's only cached wsid is wrong-build
+    (e.g. user on B42 needs `truemusic` → suggest `TrueMoozic`'s wsid).
+    When provided, each 'missing' warning is augmented with `actions:
+    [{type: "add-wsid", wsid, modId, label}]`. Unknown deps fall back to a
+    Steam Workshop search link the user follows manually.
 
     source_wsids: optional {mod_id -> workshop_id} map of *every cached mod
     in the current sort*. Used to attach the source mod's wsid onto
@@ -120,13 +123,19 @@ def build_warnings(
             continue
         actions: List[Dict[str, str]] = []
         for dep in deps:
-            wsid = lookup.get(dep)
-            if wsid:
+            entry = lookup.get(dep)
+            if entry:
+                wsid, suggested = entry
+                # If MOD_ID_ALIASES rewrote the suggestion (B42 user needing
+                # B41 mod_id `truemusic` gets `TrueMoozic` instead), surface
+                # both names so the user understands what's being added.
+                label = (f"add {suggested}" if suggested == dep
+                         else f"add {suggested} (renamed from {dep})")
                 actions.append({
                     "type": "add-wsid",
                     "wsid": wsid,
-                    "modId": dep,
-                    "label": f"add {dep}",
+                    "modId": suggested,
+                    "label": label,
                 })
             else:
                 # No cache hit -> link to Steam Workshop search so the user
@@ -558,7 +567,7 @@ def build_response(
     mods: List[ModInfo],
     sort_result: Dict[str, Any],
     status: str,
-    wsid_lookup: Dict[str, str] | None = None,
+    wsid_lookup: Dict[str, Tuple[str, str]] | None = None,
     pz_build: str = "B42",
     is_resort: bool = False,
     selected_modids: Optional[Set[str]] = None,