fix(relay): let the rehome evidence parser read a line the director grew (#21823)

The enable workflow reads the director's `[orca-relay] regional rehome
inventory` line out of Cloud Logging and pins the whole line with one regex.
Adding `hostNotArrivedLast24Hours` in #21813 made every healthy line stop
matching, so "Read fresh aggregate completion and abort evidence" threw
"no aggregate regional rehome inventory evidence" and the fail-closed step
disabled the durable switch at control generation 26.

The parser now requires the six original fields and tolerates further ones
in any order. Extra fields stay fenced by value shape rather than by pinning
the whole line: a field must be a bare name and a non-negative integer or
`none`, so `hostId=someone` is still not a counter and cannot ride along.
An absent count reads as null, not zero, because an older director not
reporting leaks is not the same as reporting none.

`hostNotArrivedLast24Hours` and `oldestActiveAgeMs` now reach the evidence
JSON and the operator step summary.

Two guards close the chain, each verified to fail on the regression it
exists for: a census in the relay package feeds the real formatter's output
to the real parser, and a script-side test pins the parser's output to the
fields the workflow summary renders.

Claude-Session: https://claude.ai/session/ced32ebb-7155-4413-adad-1eccd14c2010

.github/workflows/cloud-operate-relay-production-rehome-job.yml

@@ -320,7 +320,7 @@ jobs:
             echo '### Regional rehome control'
             jq -r '"- mode: `\(.mode)`\n- generation: `\(.control.generation)`\n- enabled: `\(.control.enabled)`"' \
               "${RUNNER_TEMP}/relay-rehome-control.json"
-            jq -r '"- active: `\(.active)`\n- awaiting receipt: `\(.awaitingReceipt)`\n- target registered: `\(.targetRegistered)`\n- completed (24h): `\(.completedLast24Hours)`\n- aborted (24h): `\(.abortedLast24Hours)`"' \
+            jq -r '"- active: `\(.active)`\n- awaiting receipt: `\(.awaitingReceipt)`\n- target registered: `\(.targetRegistered)`\n- completed (24h): `\(.completedLast24Hours)`\n- aborted (24h): `\(.abortedLast24Hours)`\n- host not arrived (24h): `\(.hostNotArrivedLast24Hours // "not reported")`\n- oldest active age (ms): `\(.oldestActiveAgeMs // "none")`"' \
               "${RUNNER_TEMP}/relay-rehome-inventory.json"
           } >> "${GITHUB_STEP_SUMMARY}"