fix: TLS verification, cookie hardening, and proxy transport (#7)

- Renamed _ssl_ctx to _internal_ssl_ctx (explicitly scoped to internal services)
- Image proxy now uses default SSL context (TLS verification enabled for external URLs)
- Logout cookie clearing now includes HttpOnly, Secure, SameSite=Lax
- proxy.py still uses internal context (Docker services have no valid certs)

Closes #7

gateway/auth.py

@@ -58,7 +58,7 @@ def handle_logout(handler):
     delete_session(token)
     handler.send_response(200)
     handler.send_header("Content-Type", "application/json")
-    handler.send_header("Set-Cookie", "platform_session=; Path=/; Max-Age=0")
+    handler.send_header("Set-Cookie", "platform_session=; Path=/; HttpOnly; Secure; SameSite=Lax; Max-Age=0")
     resp = b'{"success": true}'
     handler.send_header("Content-Length", len(resp))
     handler.end_headers()

gateway/config.py

@@ -62,7 +62,11 @@ SESSION_MAX_AGE = int(os.environ.get("SESSION_MAX_AGE", 30 * 86400))  # 30 days
 # ── Ensure data dir exists ──
 DATA_DIR.mkdir(parents=True, exist_ok=True)
 
-# ── Shared SSL context (skip verification for internal services) ──
-_ssl_ctx = ssl.create_default_context()
-_ssl_ctx.check_hostname = False
-_ssl_ctx.verify_mode = ssl.CERT_NONE
+# ── SSL contexts ──
+# Internal: skip verification for Docker-internal services (no valid certs)
+_internal_ssl_ctx = ssl.create_default_context()
+_internal_ssl_ctx.check_hostname = False
+_internal_ssl_ctx.verify_mode = ssl.CERT_NONE
+
+# Legacy alias — to be removed once all callers are updated
+_ssl_ctx = _internal_ssl_ctx

gateway/integrations/image_proxy.py

@@ -5,7 +5,7 @@ Platform Gateway — Image proxy with domain allowlist.
 import urllib.request
 import urllib.parse
 
-from config import _ssl_ctx
+# No custom SSL context — external URLs use default TLS verification
 
 ALLOWED_IMAGE_DOMAINS = {
     "i.redd.it",
@@ -59,7 +59,7 @@ def handle_image_proxy(handler):
             "Accept": "image/*,*/*",
             "Referer": parsed.scheme + "://" + parsed.netloc + "/",
         })
-        resp = urllib.request.urlopen(req, timeout=10, context=_ssl_ctx)
+        resp = urllib.request.urlopen(req, timeout=10)
         body = resp.read()
         ct = resp.headers.get("Content-Type", "image/jpeg")
         # Only serve actual image content types