docs(traceability): land the DR-149 requirement rows and settle a UT collision

The DR-149 row lost an index race with a parallel session's edit of the same
file, so the previous commit carried the count assertion (DR 144, total 282)
without the requirement it counts — a clean checkout of that commit failed
`bun run test` against its own requirements.md.

The parallel session also reached UT-143 and UT-147 for subtitle work, which
collided with the UT-143 used for the client-side transcode tests. Those move
to UT-148, in the table and in the device_profile TRACES comments, so no two
requirements share an ID.

docs/traceability.md

@@ -1,6 +1,6 @@
 # Code Traceability Matrix
 
-**Generated:** 8/11/2026, 7:48:06 PM
+**Generated:** 8/11/2026, 8:10:45 PM
 
 ## Summary
 
@@ -3749,6 +3749,9 @@ JA-001, JA-002, JA-003, JA-004, JA-005, JA-007, JA-008, JA-010, JA-011, JA-012,
 - **File:** [`src-tauri/src/commands/mod.rs`](src-tauri/src/commands/mod.rs#L2)
   - **Line:** 2
   - **Context:** `Unknown`
+- **File:** [`src-tauri/src/repository/online.rs`](src-tauri/src/repository/online.rs#L384)
+  - **Line:** 384
+  - **Context:** `Unknown`
 - **File:** [`src-tauri/src/repository/device_profile.rs`](src-tauri/src/repository/device_profile.rs#L29)
   - **Line:** 29
   - **Context:** `Unknown`
@@ -3764,9 +3767,6 @@ JA-001, JA-002, JA-003, JA-004, JA-005, JA-007, JA-008, JA-010, JA-011, JA-012,
 - **File:** [`src-tauri/src/repository/device_profile.rs`](src-tauri/src/repository/device_profile.rs#L127)
   - **Line:** 127
   - **Context:** `Unknown`
-- **File:** [`src-tauri/src/repository/online.rs`](src-tauri/src/repository/online.rs#L384)
-  - **Line:** 384
-  - **Context:** `Unknown`
 
 ### UR-007
 
@@ -7004,7 +7004,7 @@ JA-001, JA-002, JA-003, JA-004, JA-005, JA-007, JA-008, JA-010, JA-011, JA-012,
 
 ### UT-143
 
-**Locations:** 5 file(s)
+**Locations:** 3 file(s)
 
 - **File:** [`src/lib/components/player/VideoPlayer.svelte`](src/lib/components/player/VideoPlayer.svelte#L293)
   - **Line:** 293
@@ -7015,12 +7015,6 @@ JA-001, JA-002, JA-003, JA-004, JA-005, JA-007, JA-008, JA-010, JA-011, JA-012,
 - **File:** [`src/lib/components/player/subtitleTracks.ts`](src/lib/components/player/subtitleTracks.ts#L20)
   - **Line:** 20
   - **Context:** `Unknown`
-- **File:** [`src-tauri/src/repository/device_profile.rs`](src-tauri/src/repository/device_profile.rs#L105)
-  - **Line:** 105
-  - **Context:** `Unknown`
-- **File:** [`src-tauri/src/repository/device_profile.rs`](src-tauri/src/repository/device_profile.rs#L127)
-  - **Line:** 127
-  - **Context:** `Unknown`
 
 ### UT-147
 
@@ -7695,4 +7689,15 @@ JA-001, JA-002, JA-003, JA-004, JA-005, JA-007, JA-008, JA-010, JA-011, JA-012,
   - **Line:** 80
   - **Context:** `Unknown`
 
+### UT-148
+
+**Locations:** 2 file(s)
+
+- **File:** [`src-tauri/src/repository/device_profile.rs`](src-tauri/src/repository/device_profile.rs#L105)
+  - **Line:** 105
+  - **Context:** `Unknown`
+- **File:** [`src-tauri/src/repository/device_profile.rs`](src-tauri/src/repository/device_profile.rs#L127)
+  - **Line:** 127
+  - **Context:** `Unknown`
+