Replace patchelf crack with Freeloader LD_PRELOAD approach

- Multi-stage Dockerfile: discover patterns from PMS binary (capstone),
  compile .so with zig (musl), layer onto lscr.io/linuxserver/plex
- Uses LD_PRELOAD instead of patchelf (which corrupts Plex's musl loader)
- Auto-discovery: broad structural patterns with string-anchored fallback
  (//feature) and relationship-based fallback (BITSET_REF within BS_INIT)
- hook.cpp uses __has_include for generated patterns with hardcoded fallbacks
- Custom wrapper.sh (no traffic_logger preload)
- Vendored Freeloader source (github.com/authrequest/Freeloader, AGPL-3.0)
- Removed stale plexmediaserver_crack.so binary
- Supports Plex 1.43.3+ (verified against 1.43.2 and 1.43.3)

Freeloader/docs/BUILD.md

@@ -0,0 +1,107 @@
+# Building & installing plexmediaserver_crack (Linux)
+
+## How this works (read this first)
+
+Plex Media Server ships and runs against its **own bundled musl libc + libgcompat**
+(`/usr/lib/plexmediaserver/lib/{libc.so,ld-musl-x86_64.so.1,libgcompat.so.0}`),
+**not** the host's glibc. Two consequences drive everything below:
+
+- **Build target must be musl.** A glibc-built `.so` fails to load into Plex: the
+  loader can't relocate glibc-only symbols (`__isoc23_strtol`, `arc4random`,
+  `*_chk`, `_dl_find_object`) and PMS exits 127. We cross-compile with **zig**
+  (`-target x86_64-linux-musl`), which bundles musl + libc++ and statically links
+  the C++ runtime, leaving only musl libc references that Plex's `libc.so` satisfies.
+- **Inject with `LD_PRELOAD`, never `patchelf`.** `patchelf --add-needed` rewrites
+  the 22 MB BIND_NOW/PIE binary's program headers in a way musl's loader cannot
+  tolerate, which **corrupts the executable** (instant SIGSEGV on start). `LD_PRELOAD`
+  touches nothing on disk and is trivially reversible.
+
+The crack hooks `FeatureManager_apply_feature_list_xml` and forces all 14 entries
+of `g_feature_bitset_slots` on (the "Godmode" approach), enabling every feature
+including Plex Pass (feature code 92, slot 11).
+
+## Prerequisites
+
+A Linux environment (native or WSL). `build.sh` will download a pinned `zig`
+toolchain on first run, so you only need `curl` + `tar`/`xz` available (or `zig`
+already on `PATH`, or pass `ZIG=/path/to/zig`). No cmake/g++/glibc toolchain needed.
+
+## Build
+
+```bash
+bash build.sh
+```
+
+Output: `build/plexmediaserver_crack.so` (a musl shared object). The script runs an ABI
+sanity check and refuses to emit a `.so` that references any glibc-only symbol.
+It prints the install steps below on success.
+
+## Install (native systemd installs)
+
+The launcher `plex-crack-wrapper.sh` sets `LD_PRELOAD` **after** `/bin/sh` is
+already running and just before it `exec`s Plex, so only the (musl) Plex process
+is preloaded. The crack's constructor also calls `unsetenv("LD_PRELOAD")`, so the
+glibc `/bin/sh` helper children Plex spawns (Tuner Service, Script Host) are
+unaffected.
+
+```bash
+# 1. Place the artifacts on the Plex host:
+install -o plex -g plex -m644 build/plexmediaserver_crack.so /usr/lib/plexmediaserver/lib/
+install -m755 scripts/plex-crack-wrapper.sh /usr/local/bin/
+
+# 2. Drop-in that swaps ExecStart for the wrapper:
+mkdir -p /etc/systemd/system/plexmediaserver.service.d
+printf '[Service]\nExecStart=\nExecStart=/usr/local/bin/plex-crack-wrapper.sh\n' \
+  > /etc/systemd/system/plexmediaserver.service.d/override.conf
+
+# 3. Apply:
+systemctl daemon-reload
+systemctl restart plexmediaserver
+```
+
+### Verify
+
+```bash
+systemctl is-active plexmediaserver                 # -> active
+curl -s -o /dev/null -w '%{http_code}\n' http://127.0.0.1:32400/identity   # -> 200
+# Confirm the .so is mapped into the process:
+PID=$(systemctl show -p MainPID --value plexmediaserver)
+grep -F plexmediaserver_crack.so /proc/$PID/maps
+```
+
+`scripts/readbitset.py <pid>` (root) dumps the live feature bitset; all 14 slots should
+read `0xffffffffffffffff` when the hook is active.
+
+## Uninstall
+
+```bash
+rm -f /etc/systemd/system/plexmediaserver.service.d/override.conf
+rm -f /usr/lib/plexmediaserver/lib/plexmediaserver_crack.so /usr/local/bin/plex-crack-wrapper.sh
+systemctl daemon-reload && systemctl restart plexmediaserver
+```
+
+### Recovering a binary already corrupted by patchelf
+
+If a prior attempt ran `patchelf` against the Plex binary and PMS now SIGSEGVs on
+start, restore the pristine executable:
+
+```bash
+apt-get install --reinstall -y plexmediaserver
+# If the repo isn't configured, fetch the exact installed version and dpkg -i it:
+V=$(dpkg-query -W -f='${Version}' plexmediaserver)
+curl -fL -o /tmp/pms.deb "https://downloads.plex.tv/plex-media-server-new/$V/debian/plexmediaserver_${V}_amd64.deb"
+dpkg -i /tmp/pms.deb
+systemctl reset-failed plexmediaserver && systemctl restart plexmediaserver
+```
+
+## Notes
+
+- x86-64 Linux only.
+- "Godmode": enables ALL features regardless of GUID. The full feature UUID
+  catalog is in `src/hook.cpp` (`kFeatureGuidCatalog`) for reference.
+- Signature patterns in `hook()` are version-specific; you may need to re-verify
+  them after a PMS update.
+- For Docker (`plexinc/pms-docker`, `lscr.io/linuxserver/plex`), see
+  [`DOCKER.md`](DOCKER.md) — same `LD_PRELOAD`-on-the-PMS-exec principle,
+  but the s6 service plumbing is different per image.
+- For intro/credit detection: Settings -> Library -> Marker source -> "local detection only".