docs(spikes): Deno 2.9.7 + TS 7 compatibility spike and ADR-004

Co-Authored-By: Claude Fable 5.1 <[email protected]>

spikes/deno/logs/workerA.out.txt

@@ -0,0 +1,8 @@
+[A] worker started pid=968976 version=v1 runtime=deno 2.9.7
+[A] run=76f4d2cd step=submit-download version=v1
+[A] run=76f4d2cd step=copy-file start
+[A] run=76f4d2cd step=copy-file end
+[A] run=76f4d2cd step=register version=v1
+[A] run=76f4d2cd step=cleanup 
+[A] run=1fdbe2ec step=submit-download version=v1
+[A] run=1fdbe2ec step=copy-file start