db-mode config changes apply live in-process

settings and upstream writes now follow a prepare, commit, publish, retire
contract: candidates are built and validated before the database transaction,
published as infallible pointer swaps, and old generations retire after their
readers drain. per-query policy values snapshot once per query; upstream pool,
cache, rate limiter, sessions, api limiter, log sink, blocklist scheduler and
the query-log queue each gained one named live operation. restart_required
shrinks from every scalar key to the bind keys and web.enabled; the admin ui
drops its restart notices for everything else. file mode is unchanged.

src/tests.zig

@@ -22,6 +22,7 @@ comptime {
     _ = @import("upstream/doh_client.zig");
     _ = @import("upstream/doh_client_live_test.zig");
     _ = @import("upstream/pool.zig");
+    _ = @import("upstream/owner.zig");
     _ = @import("upstream/dot_client.zig");
     _ = @import("upstream/dot_client_live_test.zig");
     _ = @import("upstream/dot_client_integration_test.zig");
@@ -82,6 +83,7 @@ comptime {
     _ = @import("storage/events.zig");
     _ = @import("storage/events_fixture.zig");
     _ = @import("storage/logger.zig");
+    _ = @import("storage/logger_controller.zig");
     _ = @import("platform/statfs.zig");
     _ = @import("storage/disk_monitor.zig");
     _ = @import("platform/logging.zig");
@@ -110,6 +112,7 @@ comptime {
     _ = @import("web/handlers/lookup.zig");
     _ = @import("web/handlers/health.zig");
     _ = @import("web/handlers/version.zig");
+    _ = @import("web/handlers/apply.zig");
     _ = @import("web/handlers/mutations.zig");
     _ = @import("web/handlers/groups.zig");
     _ = @import("web/handlers/blocklists.zig");