Merge bb96e31381 into d403044f76

## Rationale 

I have 2 wifi access points with almost identical names, just one has
`_EXT` at the end of it. With the current display limit of 13 characters
before adding ellipsis, I can't tell which is which.

Before device screenshot with masked SSIDs:
<img
src="https://github.com/user-attachments/assets/3c5cbbaa-b2f6-412f-b5a8-6278963bd0f2"
width="300">


## Summary

Adjusted displayed length from 13 characters to 30 in the Wifi selection
screen - I've left some space for potential proportional font changes in
the future

After image with masked SSIDs:
<img
src="https://github.com/user-attachments/assets/c5f0712b-bbd3-4eec-9820-4693fae90c9f"
width="300">

---

### AI Usage

While CrossPoint doesn't have restrictions on AI tools in contributing,
please be transparent about their usage as it
helps set the right context for reviewers.

Did you use AI tools to help write this code? _**< NO >**_

docs/webserver.md

@@ -153,7 +153,7 @@ Click **File Manager** to access file management features.
 
 1. Click the **+ Add** button in the top-right corner
 2. Select **New Folder** from the dropdown menu
-3. Enter a folder name (letters, numbers, underscores, and hyphens only)
+3. Enter a folder name (must not contain characters \" * : < > ? / \\ | and must not be . or ..)
 4. Click **Create Folder**
 
 This is useful for organizing your ebooks by genre, author, or series.

src/activities/network/WifiSelectionActivity.cpp

@@ -546,8 +546,8 @@ void WifiSelectionActivity::renderNetworkList() const {
 
       // Draw network name (truncate if too long)
       std::string displayName = network.ssid;
-      if (displayName.length() > 16) {
-        displayName.replace(13, displayName.length() - 13, "...");
+      if (displayName.length() > 33) {
+        displayName.replace(30, displayName.length() - 30, "...");
       }
       renderer.drawText(UI_10_FONT_ID, 20, networkY, displayName.c_str());
 

src/network/html/FilesPage.html

@@ -1146,10 +1146,10 @@ function retryAllFailedUploads() {
       return;
     }
 
-    // Validate folder name (no special characters except underscore and hyphen)
-    const validName = /^[a-zA-Z0-9_\-]+$/.test(folderName);
+    // Validate folder name
+    const validName = /^(?!\.{1,2}$)[^"*:<>?\/\\|]+$/.test(folderName);
     if (!validName) {
-      alert('Folder name can only contain letters, numbers, underscores, and hyphens.');
+      alert('Folder name cannot contain \" * : < > ? / \\ | and must not be . or ..');
       return;
     }