Sanitize codebase, reorganize docs, and add missing deploy files

Remove dead code identified in docs/SANITIZATION-REVIEW.md:
- app/blueprints/content_old.py and app/blueprints/playlist.py
- app/models/group.py, app/utils/nginx_config_reader.py
- orphaned templates (content_list, edit_content, upload_content,
  player_page) and the related group/Template references

Result: 6 blueprints, 82 routes, no dead modules or orphan templates.

Add files that deploy.sh and docker-entrypoint.sh already require but
which were never tracked:
- https_manager.py       (referenced by deploy.sh, migrate_network.sh,
                          docker-entrypoint.sh)
- Caddyfile.example      (seeded by deploy.sh; its absence aborts deploy)

Relocate generated Graphify artifacts from graphify-out/ to
docs/graphify-out/ (110 files, no content change) and archive the
superseded docs under docs/.

Ignore hygiene:
- ignore ad-hoc .env backups (.env.bak*) — they contain live secrets
- keep the pre-sanitization snapshots (docs/legacy code/,
  docs/old_code_documentation/) on disk but out of the repo

Fix .env.example: drop a duplicated config block, genericize the
hardcoded host IP, and document HOSTNAME_INTERNAL.

docs/tools/test_https_manager.py

@@ -0,0 +1,75 @@
+"""Exercise https_manager.py exactly as deploy.sh does, inside a container-like env.
+
+Overrides the Caddyfile path (the only host-only difference) to prove the
+enable/status/disable flow and the resulting Caddyfile content.
+"""
+import os
+import sys
+import tempfile
+
+tmp = tempfile.mkdtemp()
+os.environ['DATABASE_URL'] = f'sqlite:///{tmp}/t.db'
+
+from app.app import create_app
+from app.models.https_config import HTTPSConfig
+from app.utils.caddy_manager import CaddyConfigGenerator
+
+app = create_app('production')
+with app.app_context():
+    from app.extensions import db
+    db.create_all()
+
+# Redirect the Caddyfile write/read to a temp path (the only host difference).
+_target = f'{tmp}/Caddyfile'
+CaddyConfigGenerator.write_caddyfile = staticmethod(
+    lambda content, path=_target: (open(_target, 'w').write(content), True)[1])
+CaddyConfigGenerator.reload_caddy = staticmethod(lambda: True)
+
+sys.argv = ['https_manager.py', 'enable', 'digiserver', '',
+            'admin@example.com', '192.168.0.152', '8443']
+
+import importlib.util
+spec = importlib.util.spec_from_file_location('hm', '/home/scheianu/digiserver-v2/https_manager.py')
+hm = importlib.util.module_from_spec(spec)
+spec.loader.exec_module(hm)
+
+print('=== ENABLE (empty domain -> internal CA) ===')
+rc = hm.main()
+print('exit code:', rc)
+
+print()
+print('=== resulting Caddyfile site blocks ===')
+text = open(_target).read()
+for ln in text.splitlines():
+    s = ln.strip()
+    if s.startswith(('http://', 'https://', ':80')) or 'tls internal' in s or 'redir' in s:
+        print('   ', s)
+
+with app.app_context():
+    c = HTTPSConfig.get_config()
+    print()
+    print('=== stored config ===')
+    print('   https_enabled:', c.https_enabled)
+    print('   domain       :', repr(c.domain))
+    print('   ip_address   :', c.ip_address)
+    print('   port         :', c.port)
+    assert c.https_enabled is True
+    assert not c.domain, 'domain must be empty for internal CA'
+    assert 'tls internal' in text, 'internal CA directive missing'
+    assert 'http://192.168.0.152' in text, 'HTTP fallback missing'
+
+print()
+print('ASSERT PASS: internal CA + HTTP fallback generated correctly')
+
+print()
+print('=== STATUS ===')
+sys.argv = ['https_manager.py', 'status']
+hm.main()
+
+print()
+print('=== DISABLE ===')
+sys.argv = ['https_manager.py', 'disable']
+hm.main()
+with app.app_context():
+    c = HTTPSConfig.get_config()
+    print('   https_enabled after disable:', c.https_enabled)