Install patches via sceAppInstUtilAppInstallPkg; fix GetInstallStatus ABI

sceAppInstUtilInstallByPackage returns 0x80B21163 from payload context
(process privilege rejection). sceAppInstUtilAppInstallPkg accepts the
same PKG with rc=0 and does install it. Switch all install paths to use
AppInstallPkg.

do_install (cross-region): require assembled PKG from the manifest
download; InstallByPackage and DP.pkg fallbacks are removed since both
are dead ends in this process context. do_install (same-region): also
switched to AppInstallPkg. do_download: removed the DP.pkg shortcut so
the manifest-assembled full PKG is downloaded as before.

sceAppInstUtilGetInstallStatus ABI: first arg is an output buffer for
the current install's content_id, not an input query. Passing our
tracking buffer there was overwriting it with zeros (disc game has no
explicit content_id). Fix: use a fresh output buffer; keep `cid` from
g_last_content_id untouched. Also add 2048-byte padding to
ai_install_status_t against firmware struct size variance.

New APIs: patchdl_install_by_uri, patchdl_install_app_pkg,
patchdl_install_debug_state. New endpoints: /api/install_uri,
/api/install_aip, /api/debug_install. delta_url propagated through
verxml → scan → websrv for future DP.pkg tracking.

Verified on device (FW 11.60, BD-JB+PPPwn): Dead Island 2 PPSA03099
updated from 01.000.001 to 01.000.011.

src/patchdl_verxml.c

@@ -148,6 +148,8 @@ parse_packages(const char *xml, uint32_t fw_bin, patchdl_verinfo_t *out) {
                             sizeof(out->compatible_version) - 1);
                     strncpy(out->compatible_url, murl[0] ? murl : durl,
                             sizeof(out->compatible_url) - 1);
+                    if (durl[0])
+                        strncpy(out->delta_url, durl, sizeof(out->delta_url) - 1);
                     extract_title_id(durl, out->compatible_storage_title,
                                      sizeof(out->compatible_storage_title));
                     if (root_title[0]) {