Add pending upload indicator to UI

This commit introduces a visual indicator in the UI to show when a case
has pending uploads.

The `WorkerSnapshot` struct has been updated to include a
`pending_case_ids` field, which is an `Arc<HashSet<Uuid>>`. This set
stores the IDs of cases that currently have files in the pending
directory.

The `run_loop` function now populates this set by scanning the pending
directory and collecting the `case_id`s of any files found. This
snapshot is then sent to the UI via the `worker_rx` channel.

In the `DoctateApp::ui` method, the `pending_ids` set is cloned from the
worker's snapshot. If a case's ID is present in this set, a distinct "⬆"
prefix and a yellow label are used to highlight it, signifying an
ongoing or pending upload. Otherwise, the standard label is used.

doctate-client-core/src/server_sync.rs

@@ -17,6 +17,7 @@
 //!   never succeed; keeping the audio around would violate the
 //!   data-minimization rule.
 
+use std::collections::HashSet;
 use std::path::{Path, PathBuf};
 use std::sync::{Arc, Mutex as StdMutex};
 use std::time::{Duration, Instant};
@@ -31,6 +32,7 @@ use reqwest::StatusCode;
 use tokio::sync::{mpsc, watch};
 use tokio::task::AbortHandle;
 use tracing::{debug, info, warn};
+use uuid::Uuid;
 
 use crate::case_store::CaseStore;
 use crate::snapshot_cache::{CachedSnapshot, SnapshotCache};
@@ -64,6 +66,10 @@ pub struct WorkerSnapshot {
     /// iteration. `0` during `Polling` / `Idle`, positive during
     /// `Uploading`.
     pub queue_len: usize,
+    /// Set of `case_id`s that currently have at least one file sitting
+    /// in the pending directory. Shared as an `Arc` so the UI can clone
+    /// the borrow cheaply and look up per-case without scanning disk.
+    pub pending_case_ids: Arc<HashSet<Uuid>>,
     /// Set to `Some(now)` after any successful upload or poll (200/304).
     /// `None` before the first success. Drives Online/Offline heuristics
     /// together with `last_failure`.
@@ -79,6 +85,7 @@ impl Default for WorkerSnapshot {
         Self {
             state: WorkerState::Idle,
             queue_len: 0,
+            pending_case_ids: Arc::new(HashSet::new()),
             last_success: None,
             last_failure: None,
         }
@@ -207,11 +214,13 @@ async fn run_loop(
 
     let publish = |state: WorkerState,
                    queue_len: usize,
+                   pending_ids: Arc<HashSet<Uuid>>,
                    last_ok: Option<Instant>,
                    last_fail: Option<Instant>| {
         let snap = WorkerSnapshot {
             state,
             queue_len,
+            pending_case_ids: pending_ids,
             last_success: last_ok,
             last_failure: last_fail,
         };
@@ -224,10 +233,18 @@ async fn run_loop(
         let mut files = scan_pending_dir(&pending_dir);
         files.sort_by(|a, b| a.recorded_at.cmp(&b.recorded_at)); // FIFO
         let queue_len = files.len();
+        let pending_ids: Arc<HashSet<Uuid>> =
+            Arc::new(files.iter().map(|u| u.case_id).collect());
         let next = files.into_iter().next();
 
         if let Some(upload) = next {
-            publish(WorkerState::Uploading, queue_len, last_success, last_failure);
+            publish(
+                WorkerState::Uploading,
+                queue_len,
+                pending_ids.clone(),
+                last_success,
+                last_failure,
+            );
             let _ = events_tx.send(UploadEvent::Started(upload.case_id));
             match post_upload(&http, &config, &upload).await {
                 UploadOutcome::Succeeded(status) => {
@@ -256,7 +273,13 @@ async fn run_loop(
                     // doesn't misreport "Uploading" during a passive wait.
                     // The footer derives "Offline" from `last_failure` being
                     // younger than `last_success`.
-                    publish(WorkerState::Idle, queue_len, last_success, last_failure);
+                    publish(
+                        WorkerState::Idle,
+                        queue_len,
+                        pending_ids.clone(),
+                        last_success,
+                        last_failure,
+                    );
                     tokio::time::sleep(backoff).await;
                     backoff = (backoff * 2).min(MAX_BACKOFF);
                 }
@@ -273,7 +296,13 @@ async fn run_loop(
                 }
             }
         } else {
-            publish(WorkerState::Polling, 0, last_success, last_failure);
+            publish(
+                WorkerState::Polling,
+                0,
+                pending_ids.clone(),
+                last_success,
+                last_failure,
+            );
             match poll_once(&http, &config, &store, &cache, &mut etag).await {
                 Ok(PollOutcome::Success) | Ok(PollOutcome::NotModified) => {
                     let now = Instant::now();
@@ -290,7 +319,13 @@ async fn run_loop(
                 }
             }
 
-            publish(WorkerState::Idle, 0, last_success, last_failure);
+            publish(
+                WorkerState::Idle,
+                0,
+                pending_ids.clone(),
+                last_success,
+                last_failure,
+            );
 
             // Wait for next tick OR kick. Cancel-safe on both arms.
             tokio::select! {