Bug/fix minor bugs

[zfoong]

What and Why
There are a few minor bugs to fix. Batch and fix them together.

Items changes/features added

• Cancel task feature added for task waiting for response
• Bug fix: Trigger description pollution and memory query issues
• User messages now stored in trigger payload instead of appending to description
• Memory queries now use task instruction + recent conversation (both user and agent messages)
• Removed string parsing logic in favor of payload-based message passing
• Fix MCPs and Skills card in dashboard, they now show usage correctly
• Fix MCP tool call issue: chunk exceeds the limit issue
• Remove agent_logs.txt logging, which caused lag and action delay after a long run