Parse every config value through a single declared type at save, boot,
and validate, and expose the settings seam from the terminal so
operators can list, set, clear, and validate overrides without SQL.
Register bool and duration ConfigSpec keys from the Default's type, move
fedwiki's four sync knobs and discourse's two into their integrations'
ConfigSpecs, and replace core's read of fedwiki-custom-domain-target
with a core domains-connect-target key resolved once and threaded
through server and worker config.
Generate init's optional-integration scaffold sections from each
registered ConfigSpec instead of the hand-maintained list, and reword
the Temporal boot warning generically.
Archives the integration-config-parity change; status bookkeeping and
the verify-skill doc follow with the test-stack commit.
cgalo5758