PatchDL 0.0.1: scan, resolve, download and install PS5 game patches

Standalone PS5 payload with an embedded web UI on :12880, no etaHEN.

- Scans installed titles and classifies the source (genuine install,
  ShadowMountPlus mount, preinstall, unknown) from the on-disk layout.
- Reads name, installed version and the Sony version.xml URL from the PS5
  app database (vendored SQLite).
- Resolves version.xml past nanoDNS via a raw DNS query, TLS pinned to the
  SCEI DNAS root.
- Filters patches to the newest one compatible with the current firmware.
- Downloads the patch and installs it through AppInstUtil (sysmodule loaded
  at runtime), gated to genuine installs with a package title-id match guard.
- Action-based UI filters and an on-screen startup notification with the URL.

src/patchdl_install.h

@@ -0,0 +1,25 @@
+#pragma once
+
+#include <stddef.h>
+
+/*
+ * Install a local PKG (a downloaded patch) via Sony's AppInstUtil service.
+ * `local_path` is the on-disk path under /data/patchdl/... The install runs
+ * asynchronously in the system installer queue once started; this returns 0
+ * when the install was accepted, non-zero (the SCE error code) otherwise, and
+ * writes a short human-readable status into `msg`.
+ *
+ * This MODIFIES the installed game. The caller must gate it to genuine
+ * (official) titles and obtain explicit user intent before calling.
+ */
+/* `expected_title_id` is the title id of the installed game the patch is for.
+   The PKG's own title id is read and must match, else the install is refused
+   (prevents a cross-region/cross-title package being installed as a new
+   phantom title). */
+int patchdl_install_local_pkg(const char *local_path,
+                              const char *expected_title_id,
+                              char *msg, size_t msg_sz);
+
+/* Verify the AppInstUtil backend can be loaded + resolved + initialized,
+   WITHOUT performing any install. Returns 0 if ready. Safe to call. */
+int patchdl_install_backend_check(char *msg, size_t msg_sz);