fix: restore clean Dockerfile, only remove pywin32 from requirements

Remove the broken multi-line Python block. Only keep the targeted
pywin32 removal (other pins are handled via apt-installed packages
python3-cffi).

Dockerfile

@@ -33,26 +33,7 @@ RUN export SABNZBD_VERSION=3.7.2 PAR2CMDLINE_VERSION=v0.6.14-mt1 && \
     curl -SL -o /tmp/sabnzbd.tar.gz https://github.com/sabnzbd/sabnzbd/releases/download/${SABNZBD_VERSION}/SABnzbd-${SABNZBD_VERSION}-src.tar.gz && \
     tar xzf /tmp/sabnzbd.tar.gz && \
     mv SABnzbd-* sabnzbd && \
-    python3 -c "
-import re
-with open('/sabnzbd/requirements.txt') as f:
-    lines = f.readlines()
-filtered = []
-for line in lines:
-    stripped = line.strip()
-    # Keep comments and blank lines
-    if not stripped or stripped.startswith('#'):
-        filtered.append(line)
-        continue
-    # Remove platform-specific packages (Windows, macOS)
-    if re.search(r'platform_system\s*==\s*[\"\\'](Windows|Darwin)[\"\\']', stripped):
-        continue
-    # Unpin to let pip resolve with system versions
-    line = re.sub(r'(==|>=|<=|!=|~=|<|>)[\d\.\*\+\-a-zA-Z]+', '', line, count=1)
-    filtered.append(line)
-with open('/sabnzbd/requirements.txt', 'w') as f:
-    f.writelines(filtered)
-" && \
+    sed -i '/pywin32/d' /sabnzbd/requirements.txt && \
     pip3 install -r /sabnzbd/requirements.txt && \
     chown -R sabnzbd: sabnzbd && \
     curl -o /tmp/par2cmdline-mt.tar.gz https://codeload.github.com/jkansanen/par2cmdline-mt/tar.gz/${PAR2CMDLINE_VERSION} && \