feat: MAJOR - implement webhook-first architecture with database priority

Revolutionary Workflow Changes (v0.7.0):
This fundamentally changes how NFOGuard handles timestamps and processing priority.

Webhooks = Source of Truth:
- First webhook fires → Use current timestamp → Store as permanent database entry
- Subsequent webhooks (upgrades) → Check database → Use original first-seen timestamp
- No more API calls during webhook processing → Webhook timing is ultimate authority
- Movies and TV episodes both use webhook-first approach

Manual Scans = Smart Fallback Logic:
- Priority 1: Our database (webhook timestamps) - database always wins
- Priority 2: Sonarr/Radarr import history (first import only)
- Priority 3: Air date as dateadded (final fallback)

Technical Implementation:
- Enhanced _get_webhook_episode_date() to use current timestamp as source of truth
- Added webhook_mode parameter to process_movie() for separate webhook logic
- All manual scans prioritize database entries before making API calls
- All timestamps converted to container timezone (Eastern Time)
- Enhanced debug logging for database lookups and timestamp decisions

Expected Workflow:
First download at 8:30am → webhook timestamp stored in database
Upgrade at 2:00pm → database entry found → original 8:30am timestamp preserved
Manual scan → database entry found → 8:30am timestamp used

This ensures the first-seen webhook timestamp is the permanent source of truth,
with upgrades and manual scans always preserving the original download time.

SUMMARY.md

@@ -327,6 +327,55 @@ sonarr-nfo-cache  | [2025-09-14T09:37:00-04:00] INFO: Batched movie webhook...
 
 ---
 
+---
+
+### 🆕 v0.7.0 MAJOR: Webhook-First Architecture & Database Priority (September 2025)
+
+**🎯 Revolutionary Workflow Changes:**
+This is a **major architectural change** that fundamentally alters how NFOGuard handles timestamps.
+
+**📡 Webhooks = Source of Truth:**
+- **First webhook seen** → Use current timestamp → Store as **permanent source of truth**
+- **Subsequent webhooks** (upgrades) → Check database → **Use original first-seen timestamp**  
+- **No more API calls during webhooks** → Webhook timing is the ultimate authority
+
+**🔍 Manual Scans = Smart Fallback Logic:**
+- **Priority 1**: Our database (webhook timestamps) → **Database always wins**
+- **Priority 2**: Sonarr/Radarr import history (first import only)
+- **Priority 3**: Air date as dateadded (final fallback)
+
+**⚡ Implementation Details:**
+- **TV Episodes**: Enhanced `_get_webhook_episode_date()` → uses current timestamp as source of truth
+- **Movies**: New webhook mode in `process_movie()` → separate logic for webhooks vs manual scans
+- **Database Priority**: Manual scans now **always** check database first before API calls
+- **Local Timezone**: All timestamps converted to container timezone (Eastern Time)
+
+**🛠️ Technical Changes:**
+- **Webhook Sources**: Episodes/movies show `webhook:first_seen` instead of complex API sources
+- **Database Verification**: Added immediate verification logging after database writes
+- **Enhanced Debug**: Comprehensive logging shows database lookups and timestamp decisions
+- **Clean Separation**: Webhook processing vs manual scan processing use different code paths
+
+**📋 Expected Workflow:**
+```
+# First Download (8:30am EST)
+Webhook fires → Use 8:30am timestamp → Store in database → NFO shows 8:30am
+
+# Upgrade Download (2:00pm EST)  
+Webhook fires → Check database → Find 8:30am entry → NFO still shows 8:30am
+
+# Manual Scan
+Curl scan → Check database → Find 8:30am webhook entry → NFO shows 8:30am
+```
+
+**🏆 Benefits:**
+- **Consistent Timestamps**: First download time is preserved forever
+- **Simplified Logic**: Webhooks don't query APIs, just use current time
+- **Performance**: Faster webhook processing with database-first approach
+- **Predictable**: Clear hierarchy - database beats everything else
+
+---
+
 **Last Updated:** September 14, 2025  
-**Version:** v0.6.7  
-**Status:** Enhanced Production Ready
+**Version:** v0.7.0  
+**Status:** Production Ready - Major Architecture