debug(reading): add comprehensive logging for position restore and save

Add detailed console logs to trace:
- Position collection and stabilization
- Save scheduling, suppression, and execution
- Restore calculations and decisions
- Scroll deltas and thresholds

Logs use [reading-position] prefix with emoji indicators for easy filtering and visual scanning.

src/components/ContentPanel.tsx

@@ -162,20 +162,24 @@ const ContentPanel: React.FC<ContentPanelProps> = ({
   // Callback to save reading position
   const handleSavePosition = useCallback(async (position: number) => {
     if (!activeAccount || !relayPool || !eventStore || !articleIdentifier) {
+      console.log('[reading-position] ❌ Cannot save: missing dependencies')
       return
     }
     if (!settings?.syncReadingPosition) {
+      console.log('[reading-position] ⚠️ Save skipped: sync disabled in settings')
       return
     }
     
     // Check if content is long enough to track reading progress
     if (!shouldTrackReadingProgress(html, markdown)) {
+      console.log('[reading-position] ⚠️ Save skipped: content too short')
       return
     }
 
     const scrollTop = window.pageYOffset || document.documentElement.scrollTop
 
     try {
+      console.log('[reading-position] 🚀 Publishing position', Math.round(position * 100) + '% to relays...')
       const factory = new EventFactory({ signer: activeAccount })
       await saveReadingPosition(
         relayPool,
@@ -188,8 +192,9 @@ const ContentPanel: React.FC<ContentPanelProps> = ({
           scrollTop
         }
       )
+      console.log('[reading-position] ✅ Position published successfully')
     } catch (error) {
-      console.error('[progress] ❌ ContentPanel: Failed to save reading position:', error)
+      console.error('[reading-position] ❌ Failed to save reading position:', error)
     }
   }, [activeAccount, relayPool, eventStore, articleIdentifier, settings?.syncReadingPosition, html, markdown])
 
@@ -217,12 +222,15 @@ const ContentPanel: React.FC<ContentPanelProps> = ({
   // Load saved reading position when article loads (stabilized one-shot restore)
   useEffect(() => {
     if (!isTextContent || !activeAccount || !relayPool || !eventStore || !articleIdentifier) {
+      console.log('[reading-position] ⏭️ Restore skipped: missing dependencies or not text content')
       return
     }
     if (settings?.syncReadingPosition === false) {
+      console.log('[reading-position] ⏭️ Restore skipped: sync disabled in settings')
       return
     }
 
+    console.log('[reading-position] 🔄 Initiating restore for article:', articleIdentifier)
     const collector = collectReadingPositionsOnce({
       relayPool,
       eventStore,
@@ -232,7 +240,12 @@ const ContentPanel: React.FC<ContentPanelProps> = ({
     })
 
     collector.onStable((bestPosition) => {
-      if (!bestPosition) return
+      if (!bestPosition) {
+        console.log('[reading-position] ℹ️ No position to restore')
+        return
+      }
+
+      console.log('[reading-position] 🎯 Stable position received:', Math.round(bestPosition.position * 100) + '%')
 
       // Wait for content to be fully rendered
       setTimeout(() => {
@@ -242,13 +255,25 @@ const ContentPanel: React.FC<ContentPanelProps> = ({
         const currentTop = window.pageYOffset || document.documentElement.scrollTop
         const targetTop = bestPosition.position * maxScroll
 
+        console.log('[reading-position] 📐 Restore calculation:', {
+          docHeight: docH,
+          winHeight: winH,
+          maxScroll,
+          currentTop,
+          targetTop,
+          targetPercent: Math.round(bestPosition.position * 100) + '%'
+        })
+
         // Skip if delta is too small (< 48px or < 5%)
         const deltaPx = Math.abs(targetTop - currentTop)
         const deltaPct = maxScroll > 0 ? Math.abs((targetTop - currentTop) / maxScroll) : 0
         if (deltaPx < 48 || deltaPct < 0.05) {
+          console.log('[reading-position] ⏭️ Restore skipped: delta too small (', deltaPx, 'px,', Math.round(deltaPct * 100) + '%)')
           return
         }
 
+        console.log('[reading-position] 📜 Restoring scroll position (delta:', deltaPx, 'px,', Math.round(deltaPct * 100) + '%)')
+
         // Suppress saves briefly to avoid feedback loop
         if (suppressSavesFor) {
           suppressSavesFor(1500)
@@ -259,10 +284,14 @@ const ContentPanel: React.FC<ContentPanelProps> = ({
           top: targetTop,
           behavior: 'auto'
         })
+        console.log('[reading-position] ✅ Scroll restored to', Math.round(bestPosition.position * 100) + '%')
       }, 500) // Give content time to render
     })
 
-    return () => collector.stop()
+    return () => {
+      console.log('[reading-position] 🛑 Stopping restore collector')
+      collector.stop()
+    }
   }, [isTextContent, activeAccount, relayPool, eventStore, articleIdentifier, settings?.syncReadingPosition, selectedUrl, suppressSavesFor])
 
   // Save position before unmounting or changing article

src/hooks/useReadingPosition.ts

@@ -34,7 +34,9 @@ export const useReadingPosition = ({
 
   // Suppress auto-saves for a given duration (used after programmatic restore)
   const suppressSavesFor = useCallback((ms: number) => {
-    suppressUntilRef.current = Date.now() + ms
+    const until = Date.now() + ms
+    suppressUntilRef.current = until
+    console.log('[reading-position] 🛡️ Suppressing saves for', ms, 'ms until', new Date(until).toISOString())
   }, [])
 
   // Debounced save function
@@ -49,6 +51,7 @@ export const useReadingPosition = ({
         clearTimeout(saveTimerRef.current)
         saveTimerRef.current = null
       }
+      console.log('[reading-position] 💾 Instant save at 100% completion')
       lastSavedPosition.current = 1
       hasSavedOnce.current = true
       lastSavedAtRef.current = Date.now()
@@ -80,7 +83,9 @@ export const useReadingPosition = ({
       }
       const remaining = Math.max(0, MIN_INTERVAL_MS - (nowMs - lastSavedAtRef.current))
       const delay = Math.max(autoSaveInterval, remaining)
+      console.log('[reading-position] ⏱️ Rescheduling save in', delay, 'ms (pos:', Math.round(currentPosition * 100) + '%)')
       saveTimerRef.current = setTimeout(() => {
+        console.log('[reading-position] 💾 Auto-save (rescheduled) at', Math.round(currentPosition * 100) + '%')
         lastSavedPosition.current = currentPosition
         hasSavedOnce.current = true
         lastSavedAtRef.current = Date.now()
@@ -96,7 +101,9 @@ export const useReadingPosition = ({
 
     // Schedule new save using the larger of autoSaveInterval and MIN_INTERVAL_MS
     const delay = Math.max(autoSaveInterval, MIN_INTERVAL_MS)
+    console.log('[reading-position] ⏱️ Scheduling save in', delay, 'ms (pos:', Math.round(currentPosition * 100) + '%)')
     saveTimerRef.current = setTimeout(() => {
+      console.log('[reading-position] 💾 Auto-save at', Math.round(currentPosition * 100) + '%')
       lastSavedPosition.current = currentPosition
       hasSavedOnce.current = true
       lastSavedAtRef.current = Date.now()
@@ -111,6 +118,7 @@ export const useReadingPosition = ({
       clearTimeout(saveTimerRef.current)
       saveTimerRef.current = null
     }
+    console.log('[reading-position] 💾 saveNow() called at', Math.round(position * 100) + '%')
     lastSavedPosition.current = position
     hasSavedOnce.current = true
     lastSavedAtRef.current = Date.now()
@@ -145,6 +153,9 @@ export const useReadingPosition = ({
       // Schedule auto-save if sync is enabled (unless suppressed)
       if (Date.now() >= suppressUntilRef.current) {
         scheduleSave(clampedProgress)
+      } else {
+        const remainingMs = suppressUntilRef.current - Date.now()
+        console.log('[reading-position] 🛡️ Save suppressed (', remainingMs, 'ms remaining) at', Math.round(clampedProgress * 100) + '%')
       }
 
       // Completion detection with 2s hold at 100%

src/services/readingPositionService.ts

@@ -203,10 +203,14 @@ export function collectReadingPositionsOnce(params: {
     hasEmitted = true
 
     if (candidates.length === 0) {
+      console.log('[reading-position] 📊 No candidates collected during stabilization window')
       stableCallback(null)
       return
     }
 
+    console.log('[reading-position] 📊 Collected', candidates.length, 'position candidates:', 
+      candidates.map(c => `${Math.round(c.position * 100)}% @${new Date(c.timestamp * 1000).toLocaleTimeString()}`).join(', '))
+
     // Sort: newest first, then highest progress
     candidates.sort((a, b) => {
       const timeDiff = b.timestamp - a.timestamp
@@ -214,10 +218,13 @@ export function collectReadingPositionsOnce(params: {
       return b.position - a.position
     })
 
+    console.log('[reading-position] ✅ Best position selected:', Math.round(candidates[0].position * 100) + '%', 
+      'from', new Date(candidates[0].timestamp * 1000).toLocaleTimeString())
     stableCallback(candidates[0])
   }
 
   // Start streaming and collecting
+  console.log('[reading-position] 🎯 Starting stabilized position collector (window:', windowMs, 'ms)')
   streamStop = startReadingPositionStream(
     relayPool,
     eventStore,
@@ -225,13 +232,22 @@ export function collectReadingPositionsOnce(params: {
     articleIdentifier,
     (pos) => {
       if (hasEmitted) return
-      if (!pos) return
-      if (pos.position <= 0.05 || pos.position >= 1) return
+      if (!pos) {
+        console.log('[reading-position] 📥 Received null position')
+        return
+      }
+      if (pos.position <= 0.05 || pos.position >= 1) {
+        console.log('[reading-position] 🚫 Ignoring position', Math.round(pos.position * 100) + '% (outside 5%-100% range)')
+        return
+      }
       
+      console.log('[reading-position] 📥 Received position candidate:', Math.round(pos.position * 100) + '%', 
+        'from', new Date(pos.timestamp * 1000).toLocaleTimeString())
       candidates.push(pos)
 
       // Schedule one-shot emission if not already scheduled
       if (!timer) {
+        console.log('[reading-position] ⏰ Starting', windowMs, 'ms stabilization timer')
         timer = setTimeout(() => {
           emitStable()
           if (streamStop) streamStop()