Keep rotated log files for a set number of days

Personal-data catalog spec, default D1 (settled 2026-09-28): log files
were never deleted. inbuxa:LogSettings.keepForDays says how many days
rotated log files are kept; unset (null) keeps every file, as before,
and a new install sets 30 days.

It is a fork-owned setting, stored under T + l as audit retention is,
not a field on x:TracerLog: that object is also stored inside
x:Bootstrap with a field after it, so a new field would change
x:Bootstrap's stored format. Server-level, with the tracers'
permissions (sysTracerGet, sysTracerUpdate); changes are in the audit
log, before and after.

Log files are local, so every node deletes its own: hourly, and at once
when the setting changes on that node. Only regular files named
<prefix>.<something> in each enabled log tracer's directory, last
changed more than the limit ago, are removed; the file being written is
never that old, and nothing else in the directory is touched. Minimum
one day. The catalog classifies inbuxa:LogSettings and points the log
file's retention at it.

Tested: unit tests for the file rule (only this log's old files; the
current file, other files and directories stay) and a purge on disk;
the system suite, which reads, sets, refuses zero, restores null and
checks the audit records; fork checks.

crates/common/src/manager/defaults.rs

@@ -408,6 +408,19 @@ async fn insert_safe_defaults(bp: &mut Bootstrap) -> trc::Result<()> {
         ] {
             bp.registry.write(RegistryWrite::insert(&object)).await?;
         }
+
+        // D1: rotated log files are kept 30 days (a fork-owned setting,
+        // since x:TracerLog is also stored inside x:Bootstrap)
+        use inbuxa_features::security::log_files;
+        if !log_files::is_set(&bp.data_store).await? {
+            log_files::set(
+                &bp.data_store,
+                &log_files::LogSettings {
+                    keep_for_days: Some(log_files::NEW_INSTALL_KEEP_DAYS),
+                },
+            )
+            .await?;
+        }
     }
 
     if bp.registry.count_object(ObjectType::Role).await? == 0 {