fix(tui): responsive input, request timeouts, poisoned-stream reconnect

R1 — input latency: the event loop drained input once per iteration, then
slept the whole metrics interval; keys and wheel events queued for up to
500ms (or the full interval at slower rates) and applied in bursts. The
input block is extracted to drain_input() and the tail sleep replaced by
a deadline wait in <=33ms poll slices that handles and repaints input the
moment it arrives. Verified: help modal opens <150ms into a 2000ms tick.

R2 — freeze-proofing: metrics/processes/disks requests had no timeout; a
half-dead connection left ws.next() pending forever and froze the TUI
with no way to quit (raw mode eats Ctrl+C as an unread key event). All
requests now carry a 5s budget.

C3 — desync: replies are matched to requests by order alone, so a timed-
out request's late reply would shift every subsequent reply off by one.
Any timeout now treats the stream as poisoned and goes through the
reconnect flow — a fresh stream is aligned by construction. The modal
endpoints additionally mark process details unsupported (flag resets on
modal close/selection change) so a detail-less agent doesn't cause a
reconnect loop. While disconnected the fetch path idles: recovery belongs
to the manual/auto retry paths instead of 5s-timeout hammering.

C7 — fit::truncate_middle_cols replaces util::truncate_middle: display-
width aware and char-boundary safe; the byte-slicing version panicked the
draw loop on non-ASCII device names.

Verified live: agent kill -9 mid-session -> error modal in <3s, q exits
while disconnected, r reconnects and resumes.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

socktop/src/ui/disks.rs

@@ -1,7 +1,8 @@
 //! Disk cards with per-device gauge and title line.
 
 use crate::types::Metrics;
-use crate::ui::util::{disk_icon, human, truncate_middle};
+use crate::ui::fit::truncate_middle_cols;
+use crate::ui::util::{disk_icon, human};
 use ratatui::{
     layout::{Constraint, Direction, Layout, Rect},
     style::Style,
@@ -69,7 +70,7 @@ pub fn draw_disks(f: &mut ratatui::Frame<'_>, area: Rect, m: Option<&Metrics>) {
             "{}{}{}{}  {} / {}  ({}%)",
             indent,
             disk_icon(&d.name),
-            truncate_middle(&d.name, (slot.width.saturating_sub(6)) as usize / 2),
+            truncate_middle_cols(&d.name, slot.width.saturating_sub(6) / 2),
             temp_str,
             human(used),
             human(d.total),

socktop/src/ui/fit.rs

@@ -43,6 +43,46 @@ pub fn truncate_cols(s: &str, max: u16) -> String {
     out
 }
 
+/// Shortens `s` to at most `max` columns by cutting the MIDDLE, marking the
+/// cut with `…` — device names like `/dev/nvme0n1p1` keep their distinctive
+/// prefix and suffix. Column- and char-boundary-safe; the byte-slicing
+/// predecessor in `util.rs` panicked on non-ASCII names.
+pub fn truncate_middle_cols(s: &str, max: u16) -> String {
+    if cols(s) <= max {
+        return s.to_string();
+    }
+    if max <= 1 {
+        return truncate_cols(s, max);
+    }
+    // Reserve one column for the ellipsis; split the rest left/right.
+    let left_budget = (max - 1) / 2;
+    let right_budget = max - 1 - left_budget;
+
+    let mut left_end = 0; // byte index
+    let mut used = 0u16;
+    for (i, ch) in s.char_indices() {
+        let w = cols(ch.encode_utf8(&mut [0u8; 4]));
+        if used + w > left_budget {
+            break;
+        }
+        used += w;
+        left_end = i + ch.len_utf8();
+    }
+
+    let mut right_start = s.len();
+    let mut used = 0u16;
+    for (i, ch) in s.char_indices().rev() {
+        let w = cols(ch.encode_utf8(&mut [0u8; 4]));
+        if used + w > right_budget || i < left_end {
+            break;
+        }
+        used += w;
+        right_start = i;
+    }
+
+    format!("{}…{}", &s[..left_end], &s[right_start..])
+}
+
 /// Picks the first (richest) candidate pair that fits side by side in `width` columns
 /// with at least `gap` columns between them.
 ///
@@ -108,6 +148,23 @@ mod tests {
         assert_eq!(truncate_cols("🔒ab", 2), "…");
     }
 
+    /// Middle truncation keeps both ends — the parts that identify a device —
+    /// and must never exceed the budget or split a character.
+    #[test]
+    fn truncate_middle_keeps_both_ends_within_budget() {
+        assert_eq!(truncate_middle_cols("/dev/nvme0n1p1", 20), "/dev/nvme0n1p1");
+        let out = truncate_middle_cols("/dev/nvme0n1p1", 9);
+        assert_eq!(cols(&out), 9);
+        assert!(out.starts_with("/dev"), "{out}");
+        assert!(out.ends_with("1p1"), "{out}");
+        assert!(out.contains('…'), "{out}");
+        // Non-ASCII names must not panic (the old byte-slicing version did).
+        for max in 0..12u16 {
+            let out = truncate_middle_cols("диск-🗄️-данные", max);
+            assert!(cols(&out) <= max.max(1), "{out:?} exceeds {max}");
+        }
+    }
+
     #[test]
     fn pick_pair_takes_the_richest_that_fits() {
         let candidates = [

socktop/src/ui/util.rs

@@ -22,19 +22,6 @@ pub fn human(b: u64) -> String {
     format!("{tb:.2}TB")
 }
 
-pub fn truncate_middle(s: &str, max: usize) -> String {
-    if s.len() <= max {
-        return s.to_string();
-    }
-    if max <= 3 {
-        return "...".into();
-    }
-    let keep = max - 3;
-    let left = keep / 2;
-    let right = keep - left;
-    format!("{}...{}", &s[..left], &s[s.len() - right..])
-}
-
 pub fn disk_icon(name: &str) -> &'static str {
     let n = name.to_ascii_lowercase();
     if n.contains(':') {

socktop/tests/profiles.rs

@@ -8,6 +8,7 @@ static ENV_LOCK: Mutex<()> = Mutex::new(());
 #[allow(dead_code)] // touch crate
 fn touch() {
     let _ = socktop::types::Metrics {
+        sampled_at_ms: None,
         cpu_total: 0.0,
         cpu_per_core: vec![],
         mem_total: 0,