I2: topology guide + Component-SiteRuntime + register row 127 state that a site pair using
deployed secrets must run LocalDb replication. I3: row 127 + topology guide state the upgrade
impact (whole artifact deploy fails and reads Out of date until referenced secrets exist
centrally). M6: audit row carries secrets/missing, no removed field; removal-only deploys write
no central row. M2/M3/I1 as-built notes; CLAUDE.md secrets bullet corrected.
The site applies DeployArtifactsCommand.Secrets as the full set (rows absent from it are
soft-removed and DeployedSecretsMirror deletes them on both nodes), while null means
'central shipped no secrets' and touches nothing. The command builder shipped null for a
site with no references, so dropping the LAST secret: reference never removed the secret
from either site node. Found by the Task 13 live gate (check 5: site-a-a and site-a-b
both still held sb-gate-mxgw r1, deployed_secrets.is_removed=0 after the removal deploy).
Central now always ships a list. Old sites ignore proto field 9; the artifact hash is
unchanged (empty and null hash identically); SecretsDeployed stays null and no
DeploySiteSecrets audit row is written when nothing shipped. Regression test
NoSecretReferences_ShipsEmptySecretsList_SoTheSiteRemovesPreviouslyDeployedOnes (red
before, green after). Spec notes in Component-DeploymentManager/SiteRuntime + the design
doc's as-built section.