fix(diary): retry a daily file that failed to open

- a failed open no longer disables the writer for good: it skips records
  and tries again one minute later by its clock, or at the first record of
  a new date, whichever comes first
- the warning (still 'daily log file disabled') appears once per date
- README and the logging page describe the retry (WR-04)

docs/services/logging.md

@@ -97,7 +97,7 @@ Every record carries the attribute `component=blog`, and passes the component's
 
 A daily channel with `path: storage/logs/summer.log` writes `storage/logs/summer-2026-10-21.log` today and `storage/logs/summer-2026-10-22.log` after local midnight. A relative path resolves against the application root, the directory that holds `config/`, and may not leave it; an absolute path is used as given. Files are created with mode 0640 in directories created with mode 0750, because logs carry user identifiers, and a file is only created once a record reaches it. With `days: 14` the files of today and the 13 days before are kept and older files of the same name pattern are deleted; other files in the directory are never touched. `days: 0` keeps every file.
 
-If the directory cannot be created or the file cannot be opened (a read-only container filesystem, missing permissions), the channel logs one warning from component `diary` on the console naming the path and the error, and is disabled. The start-up never fails because of a log file.
+If the directory cannot be created or the file cannot be opened (a read-only container filesystem, missing permissions), the channel logs a warning from component `diary` on the console naming the path and the error, once per day. It then skips records and tries to open the file again one minute later, or at the first record of the next day, whichever comes first, so a passing failure (a full disk, too many open files, a directory removed for a moment during rotation) does not end file logging until the next restart. The start-up never fails because of a log file.
 
 ## Redaction