Add network request monitoring

[Redth]

Network Request Monitoring

Adds comprehensive HTTP traffic interception and monitoring to MauiDevFlow, enabling developers to observe all HTTP requests their MAUI app makes in real-time.

Architecture

App code → HttpClient → DevFlowHttpHandler (DelegatingHandler)
                              │
                              ▼
                    NetworkRequestStore (ring buffer)
                         │              │
                    REST API        WebSocket
                  /api/network     /ws/network
                         │              │
                         ▼              ▼
              CLI: maui-devflow MAUI network

What's Included

Agent Core (in-app):

• DevFlowHttpHandler — DelegatingHandler that wraps platform handlers (AndroidMessageHandler, NSUrlSessionHandler, etc.)
• NetworkRequestStore — Thread-safe ring buffer (default 500 entries) with OnRequestCaptured event
• Auto-injection via ConfigureHttpClientDefaults in AddMauiDevFlowAgent() — zero config for DI clients
• DevFlowHttp.CreateClient() helper for non-DI HttpClients
• Body capture: text up to 256KB, binary as base64, with truncation flags
• REST endpoints: /api/network, /api/network/{id}, /api/network/clear
• WebSocket endpoint: /ws/network with replay + live streaming

AgentHttpServer:

• RFC 6455 WebSocket upgrade support (handshake, frame read/write, masking, ping/pong)
• MapWebSocket() route registration alongside MapGet/MapPost
• Header parsing in HTTP request reader

CLI Commands:

• MAUI network — Live TUI monitor (streams requests in real-time)
• MAUI network --json — JSONL streaming (one JSON object per line, AI-friendly)
• MAUI network list [--host H] [--method M] [--json] — One-shot dump
• MAUI network detail <id> — Full headers + body for a specific request
• MAUI network clear — Clear captured buffer
• Color-coded status output (2xx green, 4xx red, errors red)

Sample App:

• New NetworkTestPage with buttons to make test HTTP requests (GET, POST, 404, error)

Testing

Tested on:

• ✅ Mac Catalyst — requests captured, list/detail/clear/live monitor all working
• ✅ Android — requests captured via emulator with adb forward
• ✅ iOS Simulator — requests captured correctly

Key Design Decisions

• DelegatingHandler (not platform swizzling) — cross-platform, safe, composable
• WebSocket for live streaming (not HTTP polling) — real-time, efficient, bi-directional
• Ring buffer (not unbounded) — memory-safe for mobile apps
• Body capture limits (256KB default) — prevents memory issues with large uploads/downloads
• JSONL mode — enables AI agents to parse network traffic programmatically

CI

• Build: ✅ 0 errors
• Tests: ✅ 94/94 pass