fix(models): add serde rename for durationMs field

RawEntry.duration_ms was not decorated with #[serde(rename = "durationMs")]
so the camelCase field from JSONL was silently dropped, causing
sessions transcribe to always show Duration: 0ms.

Closes claudbg-nqxz

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

.beans/claudbg-nqxz--duration-shows-0ms-rawentryduration-ms-field-name.md

@@ -1,11 +1,11 @@
 ---
 # claudbg-nqxz
 title: Duration shows 0ms — RawEntry.duration_ms field name mismatch (durationMs vs duration_ms)
-status: todo
+status: completed
 type: bug
 priority: high
 created_at: 2026-03-30T04:44:06Z
-updated_at: 2026-03-30T04:44:06Z
+updated_at: 2026-03-30T05:02:50Z
 parent: claudbg-8vpb
 ---
 
@@ -49,3 +49,7 @@ Running against session `21fae0a8`: `grep '"durationMs":[0-9]'` finds entries li
 
 - `src/models/session.rs` — `RawEntry`, `duration_ms` field (line 33)
 - `src/models/stats.rs` — `compute_stats`, accumulates `entry.duration_ms`
+
+## Summary of Changes
+
+Added `#[serde(rename = "durationMs")]` to the `duration_ms` field on `RawEntry` in `src/models/session.rs`. No other changes needed — `compute_stats` already reads `entry.duration_ms` correctly.

src/models/session.rs

@@ -30,6 +30,7 @@ pub struct RawEntry {
     /// Timestamp string (ISO 8601).
     pub timestamp: Option<String>,
     /// Unix milliseconds of the conversation turn duration.
+    #[serde(rename = "durationMs")]
     pub duration_ms: Option<u64>,
     /// Raw JSON for any fields this struct doesn't explicitly model.
     #[serde(flatten)]