feat: add public theme endpoint to presenter view

Move theme color serving from autoupdate-service to backend presenter,
as it's a simple DB query that doesn't use autoupdate-specific features.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: boehlke

openslides_backend/http/views/presenter_view.py

@@ -39,6 +39,52 @@ def presenter_route(self, request: Request) -> RouteResponse:
         self.logger.debug("Presenter request finished successfully. Send response now.")
         return presenter_response, access_token
 
+    @route("theme", method="GET", json=False)
+    def theme_route(self, request: Request) -> RouteResponse:
+        with get_new_os_conn() as conn:
+            with conn.cursor() as curs:
+                curs.execute(
+                    "SELECT theme_id FROM organization_t WHERE id = 1"
+                )
+                row = curs.fetchone()
+                if not row or not row["theme_id"]:
+                    from ..http_exceptions import NotFound
+
+                    raise NotFound()
+
+                theme_id = row["theme_id"]
+
+                color_fields = [
+                    "primary_50", "primary_100", "primary_200", "primary_300",
+                    "primary_400", "primary_500", "primary_600", "primary_700",
+                    "primary_800", "primary_900",
+                    "primary_a100", "primary_a200", "primary_a400", "primary_a700",
+                    "accent_50", "accent_100", "accent_200", "accent_300",
+                    "accent_400", "accent_500", "accent_600", "accent_700",
+                    "accent_800", "accent_900",
+                    "accent_a100", "accent_a200", "accent_a400", "accent_a700",
+                    "warn_50", "warn_100", "warn_200", "warn_300",
+                    "warn_400", "warn_500", "warn_600", "warn_700",
+                    "warn_800", "warn_900",
+                    "warn_a100", "warn_a200", "warn_a400", "warn_a700",
+                    "headbar", "yes", "no", "abstain",
+                ]
+                columns = ", ".join(color_fields)
+                curs.execute(
+                    f"SELECT {columns} FROM theme_t WHERE id = %s",
+                    (theme_id,),
+                )
+                theme_row = curs.fetchone()
+                if not theme_row:
+                    from ..http_exceptions import NotFound
+
+                    raise NotFound()
+
+                result = {
+                    k: v for k, v in theme_row.items() if v is not None
+                }
+        return result, None
+
     @route("health", method="GET", json=False)
     def health_route(self, request: Request) -> RouteResponse:
         return {"status": "running"}, None