fix: four correctness and code-quality bugs from deep review

src/backend/claude-sdk/handler.ts

@@ -154,8 +154,11 @@ export async function handleMessage(
           if (onToolUse) {
             try {
               onToolUse(tool.name, tool.input);
-            } catch {
-              /* non-fatal */
+            } catch (err) {
+              logWarn(
+                "agent",
+                `onToolUse callback threw for ${tool.name}: ${err instanceof Error ? err.message : err}`,
+              );
             }
           }
         }

src/backend/claude-sdk/stream.ts

@@ -256,38 +256,9 @@ export function processResultMessage(
 }
 
 // ── Trailing-text fallback dedup ────────────────────────────────────────────
-
-/**
- * Normalize text for fuzzy comparison — trim, lowercase, collapse whitespace,
- * strip emoji. Used to detect whether trailing prose duplicates content
- * already delivered via `end_turn` / `send(type="text")`.
- */
-export function normalizeForDedupe(text: string): string {
-  return text
-    .trim()
-    .toLowerCase()
-    .replace(/\p{Emoji_Presentation}|\p{Extended_Pictographic}/gu, "")
-    .replace(/\s+/g, " ")
-    .trim();
-}
-
-const MIN_DEDUP_LENGTH = 10;
-
-/**
- * Returns true if `candidate` is substantively the same as any text in
- * `deliveredNorms`. "Substantively" = one is a substring of the other after
- * normalization; both must be at least MIN_DEDUP_LENGTH chars to avoid
- * dropping short legitimate replies.
- */
-export function isDuplicateOfDelivered(
-  candidate: string,
-  deliveredNorms: string[],
-): boolean {
-  if (deliveredNorms.length === 0) return false;
-  const norm = normalizeForDedupe(candidate);
-  if (norm.length < MIN_DEDUP_LENGTH) return false;
-  return deliveredNorms.some(
-    (d) =>
-      d.length >= MIN_DEDUP_LENGTH && (norm.includes(d) || d.includes(norm)),
-  );
-}
+// Re-exported from the shared module so that consumers importing from
+// stream.ts continue to work without maintaining a separate implementation.
+export {
+  normalizeForDedupe,
+  isDuplicateOfDelivered,
+} from "../shared/delivered-text.js";

src/frontend/terminal/input.ts

@@ -289,6 +289,11 @@ export function createInput(promptStr: string): InputHandler {
       paused = false;
     },
     close() {
+      if (pendingResolve) {
+        const resolve = pendingResolve;
+        pendingResolve = null;
+        resolve("");
+      }
       process.stdout.write("\x1b[?2004l");
       if (process.stdin.isTTY) process.stdin.setRawMode(false);
       process.stdin.pause();

src/storage/sessions.ts

@@ -156,7 +156,8 @@ export function getSession(chatId: string): SessionState {
     session.usage.lastResponseMs = 0;
   if (
     session.usage.fastestResponseMs === undefined ||
-    session.usage.fastestResponseMs === 0
+    session.usage.fastestResponseMs === 0 ||
+    session.usage.fastestResponseMs === null
   )
     session.usage.fastestResponseMs = Infinity;
   // Migrate sessions from before context tracking was added