refactor(observer): v7 step-aware AG Native DOM parser with data-testid/data-step-index based content extraction

- Replace CSS class-based scanning with [data-testid='conversation-view'] + [data-step-index] traversal
- New extractCleanStepText(): clone-and-strip buttons/SVG/icons before text extraction
- New extractStepContext(): step-container-aware context with header + code block
- NOISE_RE: block Material icon names, button labels, UI artifacts
- Auto DOM structure dump on first conversation-view detection
- Enhanced deep-inspect with step element + button inventory
- known-issues: document AG Native SDK API incompatibility

extension/src/http-bridge.ts

@@ -151,6 +151,25 @@ export function startHttpBridge(ctx: HttpBridgeContext, sdk: any): Promise<numbe
                     return;
                 }
 
+                // GET /status — diagnostic endpoint
+                if (req.method === 'GET' && url.pathname === '/status') {
+                    const { getStepProbeContext } = require('./step-probe');
+                    const probeCtx = getStepProbeContext();
+                    const status = {
+                        projectName: ctx.projectName,
+                        activeSessionId: probeCtx.activeSessionId || ctx.activeSessionId,
+                        lastPendingStepIndex: probeCtx.lastPendingStepIndex,
+                        sessionStalled: probeCtx.sessionStalled,
+                        wsConnected: ctx.wsBridge?.isConnected() ?? false,
+                        clickTrigger: clickTrigger ? { ...clickTrigger, ageMs: Date.now() - clickTrigger.timestamp } : null,
+                        uptime: Math.round(process.uptime()),
+                        timestamp: new Date().toISOString(),
+                    };
+                    res.writeHead(200, { 'Content-Type': 'application/json' });
+                    res.end(JSON.stringify(status, null, 2));
+                    return;
+                }
+
                 // GET /ping — health check
                 if (url.pathname === '/ping') {
                     res.writeHead(200); res.end('pong');