fix(web): show the whole last turn in the Claude response viewer's brief view

The eye button rendered `data.text`, which is one row: the last assistant
row of the transcript. A Claude answer is a median of 3 model messages
(p90 11) split around tool calls, so the brief view usually showed the tail
of an answer ("Done.", "Let me look.") and the substance appeared only after
More. The full view was fine, which is why the brief one read as broken by
comparison.

The brief view now asks `?context=turn`. The reader answers with the
assistant messages of the last ANSWERED turn (`selectLastAnsweredTurn`: the
highest `turn` that has an assistant row, so a prompt queued after the
answer does not blank the view) and the frontend renders them exactly as
the full view renders that turn: one badge, then continuation segments,
gated on the numeric `turn` as before.

`data.text` is unchanged in every context — still the last assistant row,
never `messages.at(-1)` — because agent pollers hash it. Readers that emit
no turns (Codex, the pane parser, DeepSeek, an older server) return `text`
only for `context=turn`, and the brief view keeps its single card for them.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01McLWqCWBuQYGuPMScb4Aou

src/web/routes/session-routes.ts

@@ -153,6 +153,7 @@ import {
   getLastTranscriptResponse,
   isExternalCliTranscriptMode,
   parseExternalCliTranscript,
+  selectLastAnsweredTurn,
 } from '../response-viewer-transcript.js';
 import { readDeepSeekLastResponse } from '../../deepseek-transcript.js';
 
@@ -2214,10 +2215,14 @@ export function registerSessionRoutes(
     }
 
     const query = req.query as { context?: string };
+    // `turn` is the brief view's context: the last ANSWERED turn's assistant
+    // messages, so a multi-row answer is not reduced to its final row. `text`
+    // stays the last assistant row in every mode (agent pollers hash it).
+    const wantsMessages = query.context === 'full' || query.context === 'turn';
     const claudeSessionId = session.claudeSessionId || session.id;
     const transcript = await findClaudeTranscript(projectsDir, claudeSessionId, session.id);
     if (!transcript) {
-      return query.context === 'full' ? { text: '', timestamp: '', messages: [] } : { text: '', timestamp: '' };
+      return wantsMessages ? { text: '', timestamp: '', messages: [] } : { text: '', timestamp: '' };
     }
 
     if (transcript.sessionId !== session.claudeSessionId && transcript.sessionId !== session.id) {
@@ -2233,9 +2238,17 @@ export function registerSessionRoutes(
 
     try {
       const content = await fs.readFile(transcript.path, 'utf8');
-      return parseClaudeResponseTranscript(content, query.context === 'full');
+      const parsed = parseClaudeResponseTranscript(content, wantsMessages);
+      if (query.context === 'turn') {
+        return {
+          text: parsed.text,
+          timestamp: parsed.timestamp,
+          messages: selectLastAnsweredTurn(parsed.messages ?? []),
+        };
+      }
+      return parsed;
     } catch {
-      return query.context === 'full' ? { text: '', timestamp: '', messages: [] } : { text: '', timestamp: '' };
+      return wantsMessages ? { text: '', timestamp: '', messages: [] } : { text: '', timestamp: '' };
     }
   });