fix: guard int(os.getenv()) casts against malformed env vars (#40598)

A non-numeric value in env vars like HERMES_STREAM_RETRIES,
HERMES_KANBAN_SPECIFY_MAX_TOKENS, GOOGLE_CHAT_MAX_BYTES, IRC_PORT, etc.
raised ValueError at import/init and crashed startup. Parse them safely,
falling back to the default.

Unified onto the existing utils.env_int(key, default) helper for core/
hermes_cli/tools modules instead of the original PR's three duplicate
local helpers; plugins keep minimal inline guards (no core-utils import).
All existing max()/min()/`or extra.get()` wrappers preserved.

Co-authored-by: annguyenNous <annguyenNous@users.noreply.github.com>

plugins/browser/firecrawl/provider.py

@@ -78,7 +78,10 @@ class FirecrawlBrowserProvider(BrowserProvider):
         }
 
     def create_session(self, task_id: str) -> Dict[str, object]:
-        ttl = int(os.environ.get("FIRECRAWL_BROWSER_TTL", "300"))
+        try:
+            ttl = int(os.environ.get("FIRECRAWL_BROWSER_TTL", "300"))
+        except (ValueError, TypeError):
+            ttl = 300
 
         body: Dict[str, object] = {"ttl": ttl}