feat: add network.force_ipv4 config to fix IPv6 timeout issues (#8196)

On servers with broken or unreachable IPv6, Python's socket.getaddrinfo
returns AAAA records first. urllib/httpx/requests all try IPv6 connections
first and hang for the full TCP timeout before falling back to IPv4. This
affects web_extract, web_search, the OpenAI SDK, and all HTTP tools.

Adds network.force_ipv4 config option (default: false) that monkey-patches
socket.getaddrinfo to resolve as AF_INET when the caller didn't specify a
family. Falls back to full resolution if no A record exists, so pure-IPv6
hosts still work.

Applied early at all three entry points (CLI, gateway, cron scheduler)
before any HTTP clients are created.

Reported by user @29n — Chinese Ubuntu server with unreachable IPv6 causing
timeouts on lobste.rs and other IPv6-enabled sites while Google/GitHub
worked fine (IPv4-only resolution).

cron/scheduler.py

@@ -626,6 +626,15 @@ def run_job(job: dict) -> tuple[bool, str, str, Optional[str]]:
         except Exception as e:
             logger.warning("Job '%s': failed to load config.yaml, using defaults: %s", job_id, e)
 
+        # Apply IPv4 preference if configured.
+        try:
+            from hermes_constants import apply_ipv4_preference
+            _net_cfg = _cfg.get("network", {})
+            if isinstance(_net_cfg, dict) and _net_cfg.get("force_ipv4"):
+                apply_ipv4_preference(force=True)
+        except Exception:
+            pass
+
         # Reasoning config from config.yaml
         from hermes_constants import parse_reasoning_effort
         effort = str(_cfg.get("agent", {}).get("reasoning_effort", "")).strip()