M1 step 3: Log writing and Storage Clean-up

- lib/storage_model (host-tested): FAT-safe names, daily Log paths,
  dates from Log/Capture file names, CleanupPlan by category and age,
  byte formatting
- StorageService does all card I/O on its task: queued Log lines are
  written in batches each second (dropped while Logs are paused),
  plus file listing and deletion jobs
- Settings > Storage moves into StoragePage: usage, Clean up
  (category, age with size preview, confirmation), Erase SD card
- Clock: local date for Log names
- Serial: log <text>, sd list

Verified on the device: lines land in /irc/dev/#test/2026-10-02.log
with folders created as needed.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01EhqxQ49eCju4CzKYNjZzwT

README.md

@@ -48,6 +48,8 @@ sudo usermod -aG dialout "$USER"
 | `sound on` / `sound off` | Toggles the Sound setting (beep + LED) |
 | `short` / `normal` | Screen timeouts 5 s / 10 s, or 30 s / 60 s |
 | `wifi add <ssid><TAB><password>` | Adds a Saved Network (so credentials stay out of the repo) |
+| `log <text>` | Appends a line to a test IRC Log (`/irc/dev/#test/<date>.log`) |
+| `sd list` | Lists the files of each Storage Clean-up category |
 | `wifi status` | Prints Wi-Fi state, network, signal, clock and free heap |
 
 `scripts/flash.sh` stops a running serial log first, since it would hold the port.