Fix server crashes: tcmalloc and workshop collection issues

- Add automatic tcmalloc disable in start scripts to prevent 'large alloc' segfaults
- Add warnings and documentation about workshop COLLECTION vs addon IDs
- Expand troubleshooting section with solutions for common crashes
- Document that -authkey deprecation warning can be safely ignored

Fixes:
- tcmalloc: large alloc XXXXXXX bytes == (nil) followed by Segmentation fault
- Item is not a collection! error when using addon ID instead of collection ID
- Missing 32-bit libraries warning with installation instructions

workshop/README.md

@@ -14,6 +14,25 @@ Here are some popular PropHunt workshop collections you can use:
    host_workshop_collection "YOUR_COLLECTION_ID"
    ```
 
+### ⚠️ IMPORTANT: Collection vs Addon IDs
+
+**The WORKSHOP_COLLECTION setting MUST be a Collection ID, NOT an individual addon ID!**
+
+To verify your ID is correct:
+1. Go to: `https://steamcommunity.com/sharedfiles/filedetails/?id=YOUR_ID`
+2. Look at the page - it should say **"Collection"** at the top
+3. If it says "Addon" or shows a single item, it's NOT a collection!
+
+**If you use an addon ID instead of a collection ID, you'll see this error:**
+```
+Processing collection XXXXX...
+   Item is not a collection!
+   Collection 'Name' (0 items)
+   Reported 0 items, skipping
+```
+
+**Fix:** Create your own collection containing the addons you want, or find an existing PropHunt collection.
+
 ### Essential Content to Include
 
 Your workshop collection should include: