feat: add Confluence recent pages + Sentry error tracking (MAT-58, MAT-59)

MAT-58: Add recent_confluence_pages tool to both voice and text chat.
Shows last 5 recently modified pages so users can pick directly
instead of having to search every time.

MAT-59: Integrate sentry-sdk in all three entry points (agent.py,
bot.py, voice.py). SENTRY_DSN env var, traces at 10% sample rate.
Requires creating project in Sentry UI and setting DSN.

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

requirements.txt

@@ -13,3 +13,4 @@ python-docx>=1.0,<2.0
 Pillow>=10.0,<12.0
 beautifulsoup4>=4.12
 lxml>=5.0
+sentry-sdk>=2.0,<3.0