chore: sample traces at 100%

Root spans are becoming the canonical per-request record (status code,
invocation outcome, timing), so head sampling moves to 1. Ingest cost
is controlled by VRL stripping at the Better Stack source instead.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

Author: colinmcdonald22

wrangler.jsonc

@@ -29,7 +29,7 @@
     "traces": {
       "enabled": true,
       "destinations": ["betterstack-traces"],
-      "head_sampling_rate": 0.01,
+      "head_sampling_rate": 1.0,
       "persist": true
     }
   },