docs(agents): update knowledge base with encryption, API envelope, and build conventions (#127)

Add comprehensive documentation of project conventions including:
- Encryption patterns (AES with node secret PSK)
- API envelope structure (code, msg, data, ts)
- Build peculiarities (minify: false, rolldown-vite, UPX compression)
- Unique styles (flat monorepo, asymmetric Go layout, hybrid frontend mode)
- Module boundaries and anti-patterns
- Large file hotspots and code map references

Updated 7 AGENTS.md files across root and submodules.

go-gost/x/socket/AGENTS.md

@@ -1,24 +1,32 @@
 # GOST SOCKET KNOWLEDGE BASE
 
-**Generated:** Fri Feb 13 2026
+**Generated:** Sun Feb 15 2026
 
 ## OVERVIEW
-Socket utilities and wrappers for GOST forwarding.
-**Stack:** Go, GOST core.
+WebSocket reporter and socket utilities for panel integration.
+**Stack:** Go, GOST core, gorilla/websocket.
 
 ## STRUCTURE
 ```
 socket/
-├── socket.go      # Core socket interface
-├── udp.go         # UDP socket handling
-├── packet.go      # Packet framing
-├── packetconn.go  # Packet connection wrapper
-└── ...            # Additional socket utilities
+├── websocket_reporter.go  # Agent-to-panel telemetry (1504 LOC)
+├── service.go             # Socket service orchestration (534 LOC)
+├── socket.go              # Core socket interface
+├── udp.go                 # UDP socket handling
+├── packet.go              # Packet framing
+└── packetconn.go          # Packet connection wrapper
 ```
 
+## WHERE TO LOOK
+| Task | Location | Notes |
+|------|----------|-------|
+| **Panel Reporting** | `websocket_reporter.go` | Real-time system info (CPU, mem, uptime) every 2s |
+| **Command Handling** | `websocket_reporter.go` | Processes `AddService`, `UpgradeAgent`, etc. |
+
 ## CONVENTIONS
 - Inherits from parent `go-gost/x/` conventions.
 - Low-level network primitives.
+- All panel communication is AES-encrypted using node `secret`.
 
 ## ANTI-PATTERNS
 - DO NOT EDIT generated protobuf.