Slim scheduler, add maintenance module

- Introduced a new `maintenance` module to handle data retention, log rotation, and nightly email tasks.
- Updated the `scheduler` to utilize the `MaintenanceRunner` for executing maintenance tasks, improving code organization and clarity.
- Enhanced documentation to reflect changes in logging configuration and data retention processes.
- Adjusted tests to accommodate the refactored scheduler methods and ensure proper functionality.

docs/configuration.md

@@ -20,6 +20,14 @@ The main sections include:
 | `[Weather]` | Units and settings shared by `wx` / `gwx` and Weather Service |
 | `[Logging]` | Log file path and level |
 
+### Logging and log rotation
+
+- **Startup (config.ini):** Under `[Logging]`, `log_file`, `log_max_bytes`, and `log_backup_count` are read when the bot starts. They control the initial `RotatingFileHandler` for the bot log file (see `config.ini.example`).
+
+- **Live changes (web viewer):** The Config tab can store **`maint.log_max_bytes`** and **`maint.log_backup_count`** in the database (`bot_metadata`). The scheduler’s maintenance loop applies those values to the existing rotating file handler **without restarting** the bot—**but only after** you save rotation settings from the web UI (which writes the metadata keys). Editing `config.ini` alone does not update `bot_metadata`, so hot-apply will not see a change until you save from the viewer (or set the keys another way).
+
+If you rely on config-file-only workflows, restart the bot after changing `[Logging]` rotation options.
+
 ## Channels section
 
 `[Channels]` controls where the bot responds:

docs/data-retention.md

@@ -34,7 +34,7 @@ Shorter retention (e.g. 2–3 days for `packet_stream`) is enough for the web vi
 
 ## How cleanup runs
 
-1. The **scheduler** (in the main bot process) runs a single data-retention task once every 24 hours.
+1. The **scheduler** (in the main bot process) runs a single data-retention task on a **24-hour interval** after startup (the first run is not immediate on boot; it aligns with the nightly maintenance email cadence).
 2. That task:
    - Cleans **packet_stream** (via web viewer integration when enabled).
    - Cleans **purging_log**, **daily_stats**, **unique_advert_packets**, and **observed_paths** (repeater manager).