Add user prompt text display and agents graph tab

Features:
- User prompt hook now captures and displays actual prompt text
- Added tab switching between Event Feed and Agents Graph
- Created AgentsGraph component with placeholder
- Added CSS styling for agents graph view

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

.claude/hooks/user_prompt.sh

@@ -7,18 +7,21 @@ INPUT=$(cat)
 
 # Extract fields using jq
 SESSION_ID=$(echo "$INPUT" | jq -r '.session_id // "unknown"')
-PROMPT_LENGTH=$(echo "$INPUT" | jq -r '.prompt_length // 0')
+PROMPT=$(echo "$INPUT" | jq -r '.prompt // .text // ""')
+PROMPT_LENGTH=${#PROMPT}
 TIMESTAMP=$(echo "$INPUT" | jq -r '.timestamp // (now | tonumber)')
 
 # Build payload for backend
 PAYLOAD=$(jq -n \
   --arg session_id "$SESSION_ID" \
   --arg event_type "UserPromptSubmit" \
+  --arg prompt "$PROMPT" \
   --arg prompt_length "$PROMPT_LENGTH" \
   --arg timestamp "$TIMESTAMP" \
   '{
     session_id: $session_id,
     event_type: $event_type,
+    tool_input: $prompt,
     description: ("User submitted prompt (" + $prompt_length + " chars)"),
     timestamp: ($timestamp | tonumber)
   }')