Drop leftovers of the "shared master can't install" assumption

/api/pkgmeta now calls a package installable when its embedded title id
matches the installed game, which is what AppInstallPkg goes by, instead
of flagging every shared-master package. The unused UI message for the
old refusal is gone, and web/README.md describes the current policy:
Shadowmount, unknown and fake titles get neither download nor install,
and shared-master packages install like any other.

src/patchdl_websrv.c

@@ -2647,7 +2647,9 @@ on_request(void *cls, struct MHD_Connection *conn, const char *url,
     }
 
     /* Read-only: report the .pkg's embedded content id / title id vs the target
-       (installed app) ids, to expose the cross-region linkage. No install. */
+       (installed app) ids. AppInstallPkg installs by the id inside the package,
+       so it lands on the game only when they match; where the CDN stores the
+       pieces (storage_title_id) doesn't matter. No install. */
     if (!strncmp(url, "/api/pkgmeta/", 13)) {
         const char      *tid = url + 13;
         char             purl[768] = {0}, durl_[512] = {0};
@@ -2670,13 +2672,11 @@ on_request(void *cls, struct MHD_Connection *conn, const char *url,
         snprintf(resp, sizeof resp,
                  "{\"ok\":%s,\"pkg_content_id\":\"%s\",\"pkg_title_id\":\"%s\","
                  "\"is_app\":%s,\"target_content_id\":\"%s\",\"target_title_id\":\"%s\","
-                 "\"storage_title_id\":\"%s\",\"installable\":%s,\"install_plan\":\"%s\","
-                 "\"msg\":\"%s\"}",
+                 "\"storage_title_id\":\"%s\",\"installable\":%s,"
+                 "\"install_plan\":\"appinstallpkg\",\"msg\":\"%s\"}",
                  rc == 0 ? "true" : "false", ecid, etid, is_app ? "true" : "false",
                  cid, tid, psti,
-                 (psti[0] && strncmp(psti, tid, 9) != 0) ? "false" : "true",
-                 (psti[0] && strncmp(psti, tid, 9) != 0) ?
-                    "cross_region_storage_unsupported" : "installbypackage",
+                 (rc == 0 && !strncmp(etid, tid, 9)) ? "true" : "false",
                  msg);
         return queue_json_owned(conn, MHD_HTTP_OK, strdup(resp));
     }

web/README.md

@@ -39,8 +39,9 @@ The UI assumes deny-by-default behavior:
   "source_policy": {
     "official": { "allow_check": true, "allow_download": true, "allow_install": true },
     "external": { "allow_check": true, "allow_download": true, "allow_install": true },
-    "shadowmount": { "allow_check": true, "allow_download": true, "allow_install": false },
-    "unknown": { "allow_check": true, "allow_download": false, "allow_install": false }
+    "shadowmount": { "allow_check": true, "allow_download": false, "allow_install": false },
+    "unknown": { "allow_check": true, "allow_download": false, "allow_install": false },
+    "fake": { "allow_check": true, "allow_download": false, "allow_install": false }
   },
   "cdn_allowlist": [
     "sgst.prod.dl.playstation.net",
@@ -70,7 +71,7 @@ Per-title source fields:
   "source_path": "/system_ex/app/PPSA90001_00",
   "mount_from": "/mnt/usb0/itemzflow/Shadowmounted Test Title",
   "enabled": true,
-  "mode": "download_only"
+  "mode": "disabled"
 }
 ```
 
@@ -83,16 +84,17 @@ shadowmount
 unknown
 ```
 
-The frontend treats `shadowmount` as download-only and `unknown` as blocked for
-downloads and installs. Backend code should enforce the same policy even if a
-client sends a forged request.
+The frontend lists `shadowmount`, `unknown` and `fake` titles under *Not
+supported* and offers neither download nor install for them. The backend refuses
+both as well, even if a client sends a forged request.
 
 For PS5 game updates, the backend may turn a Sony `manifest_url` into a merged
 local `.pkg` by downloading all manifest pieces. The `delta_url` `*-DP.pkg` is
 not shown as a separate user action because it can bootstrap the storage/master
 title instead of the installed regional target.
 
-If `patch_storage_match` is false, the UI keeps download/verify available but
-does not offer install or auto-install. Those shared-master packages are signed
-for a different storage title id and cannot be retargeted by standalone
-AppInstUtil on firmware 11.60.
+If `patch_storage_match` is false, the CDN stores the patch pieces under another
+regional (master) title id. That is fine: the merged `.pkg` assembled from the
+manifest carries the installed title's own content id, and AppInstUtil
+`AppInstallPkg` installs it onto that title. The UI only adds a "Shared master"
+label.

web/app.js

@@ -1102,7 +1102,6 @@ async function postJson(url, body) {
 
 const REASON_TEXT = {
   patch_title_mismatch: "Patch metadata targets a different title - install blocked.",
-  cross_region_storage_unsupported: "Patch bytes are signed for a shared master title; this standalone installer cannot retarget them.",
   install_not_allowed_for_source: "Install blocked for this source.",
   source_unknown: "Source unknown — blocked.",
   source_fake: "Fake packages are not supported.",