Add robust jpegio ARM64 patching system

- Create rpi/patches/ directory with multi-strategy patching
- Patch tries: patch file → sed → Python regex → already-patched detection
- Fix jpegio patch to handle multiple -m64 occurrences
- Update docs to use wget instead of curl|bash (stdin conflict with read)
- Update SSH examples to use admin@stegasoo.local

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

rpi/patches/jpegio/arm64.patch

@@ -0,0 +1,17 @@
+--- a/setup.py
++++ b/setup.py
+@@ -69,12 +69,12 @@
+     largs.append('-mmacosx-version-min=10.9')
+
+     if arch == 'x64':
+-        cargs.append('-m64')
++        pass  # ARM64: removed x86-specific -m64 flag
+ elif sys.platform == 'linux':
+     cargs.extend(['-w', '-fPIC'])
+
+     if arch == 'x64':
+-        cargs.append('-m64')
++        pass  # ARM64: removed x86-specific -m64 flag
+     dname_libjpeg = 'libjpeg'
+
+ # end of if-else