Add TOML dependency and new config/startup modules

The TOML dependency is added to `Cargo.lock` to support configuration
file parsing.
New modules `config` and `startup` are introduced in
`doctate-client-core`:
- `config`: Handles client configuration loading and saving, including
  defaults for polling intervals and window hours.
- `startup`: Contains routines for initial cleanup tasks, such as
  removing stale markers and orphan audio files based on defined
  retention periods.

client-desktop/src/app.rs

@@ -14,10 +14,13 @@ use std::sync::Arc;
 use std::time::{Duration, Instant};
 
 use doctate_client_core::{
-    cleanup_orphan_audio, write_sidecar, CaseMarker, CaseStore, PendingUpload, ServerSync,
-    SnapshotCache, SyncConfig, UploadEvent, WorkerSnapshot, WorkerState,
+    pick_footer_status, run_startup_cleanup, write_sidecar, CaseMarker, CaseStore, FooterStatus,
+    PendingUpload, ServerSync, SnapshotCache, SyncConfig, UploadEvent, WorkerSnapshot, WorkerState,
+    DEFAULT_MARKER_RETENTION, DEFAULT_ORPHAN_AUDIO_RETENTION,
+};
+use doctate_common::timestamp::{
+    extract_hhmm, now_rfc3339, parse_rfc3339, recorded_at_to_filename_stem,
 };
-use doctate_common::timestamp::{now_rfc3339, recorded_at_to_filename_stem};
 use eframe::egui;
 use tokio::runtime::Runtime;
 use tokio::sync::{mpsc, watch};
@@ -26,7 +29,7 @@ use uuid::Uuid;
 
 use crate::config::Config;
 use crate::recorder::{Recorder, RecorderEvent};
-use crate::state::{pick_footer_status, AppState, FooterStatus};
+use crate::state::AppState;
 
 pub struct DoctateApp {
     runtime: Arc<Runtime>,
@@ -72,7 +75,7 @@ impl DoctateApp {
         cases_dir: PathBuf,
         snapshot_cache_path: PathBuf,
     ) -> Self {
-        let config = match Config::load() {
+        let config = match crate::config::load() {
             Ok(Some(c)) => Some(c),
             Ok(None) => None,
             Err(e) => {
@@ -102,18 +105,13 @@ impl DoctateApp {
             let store = case_store.clone();
             let pending = pending_dir.clone();
             runtime.block_on(async move {
-                let marker_cutoff = time::OffsetDateTime::now_utc() - time::Duration::hours(72);
-                match store.cleanup_stale(marker_cutoff).await {
-                    Ok(n) if n > 0 => info!(count = n, "startup cleanup: stale markers removed"),
-                    Ok(_) => {}
-                    Err(e) => warn!(error = %e, "startup cleanup: marker sweep failed"),
-                }
-                let audio_cutoff =
-                    std::time::SystemTime::now() - std::time::Duration::from_secs(24 * 3600);
-                let n = cleanup_orphan_audio(&pending, audio_cutoff).await;
-                if n > 0 {
-                    info!(count = n, "startup cleanup: orphan audio removed");
-                }
+                run_startup_cleanup(
+                    &store,
+                    &pending,
+                    DEFAULT_MARKER_RETENTION,
+                    DEFAULT_ORPHAN_AUDIO_RETENTION,
+                )
+                .await;
             });
         }
 
@@ -164,7 +162,7 @@ impl DoctateApp {
                 .as_ref()
                 .and_then(|c| c.oneliner_window_hours),
         };
-        if let Err(e) = cfg.save() {
+        if let Err(e) = crate::config::save(&cfg) {
             error!(error = %e, "config save failed");
             self.state = AppState::Error {
                 message: format!("Speichern: {e}"),
@@ -641,24 +639,6 @@ fn spawn_worker(
     (sync, events_rx, snapshot_rx)
 }
 
-fn parse_rfc3339(s: &str) -> Option<time::OffsetDateTime> {
-    time::OffsetDateTime::parse(s, &time::format_description::well_known::Rfc3339).ok()
-}
-
-/// Extract `HH:MM` from an RFC3339 UTC timestamp. Returns the raw string
-/// truncated to the first 16 chars as a fallback on parse failure — the
-/// user still gets something readable.
-fn extract_hhmm(ts: &str) -> String {
-    match parse_rfc3339(ts) {
-        Some(t) => {
-            let local = t
-                .to_offset(time::UtcOffset::current_local_offset().unwrap_or(time::UtcOffset::UTC));
-            format!("{:02}:{:02}", local.hour(), local.minute())
-        }
-        None => ts.chars().take(16).collect(),
-    }
-}
-
 impl eframe::App for DoctateApp {
     fn update(&mut self, ctx: &egui::Context, _frame: &mut eframe::Frame) {
         self.drain_recorder_events();