fix(security): remove SSL verification downgrade fallback

PR_DESCRIPTION_9446.md

@@ -0,0 +1,109 @@
+# Issue #9446 - SSL Verification Downgrade Vulnerability Fix
+
+## 🔐 Security Fix
+
+This PR fixes a critical security vulnerability where `download_image_by_url()` and `download_file()` 
+would silently downgrade SSL certificate verification to `CERT_NONE` on SSL errors, allowing 
+man-in-the-middle (MITM) attacks.
+
+### Vulnerability Details
+
+**Before Fix:**
+- When SSL certificate verification failed, the code would catch the exception and retry with `ssl.CERT_NONE`
+- This fallback behavior was automatic and silent (only logged a warning)
+- Attackers could exploit this by triggering certificate errors to force insecure connections
+
+**After Fix:**
+- SSL certificate verification is always enforced
+- SSL errors raise exceptions immediately without fallback
+- No automatic downgrade to insecure connections
+
+## 🔧 Changes
+
+### Modified Functions
+
+#### `download_image_by_url()` (lines 116-144)
+- **Removed:** SSL fallback try-except block that would retry with `CERT_NONE`
+- **Behavior:** SSL certificate errors now raise immediately instead of falling back to insecure mode
+- **Impact:** Functions calling this must handle SSL exceptions explicitly
+
+#### `download_file()` (lines 250-291)
+- **Removed:** SSL fallback logic
+- **Changed:** Default parameter value `allow_insecure_ssl_fallback=False` (was `True`)
+- **Updated:** Parameter documentation to indicate it's deprecated and ignored
+- **Behavior:** Always enforces SSL verification regardless of parameter value
+
+#### `download_dashboard()` (lines 452-549)
+- **Updated:** Parameter documentation for `allow_insecure_ssl_fallback` 
+- **Documentation:** Now indicates the parameter is deprecated and ignored
+- **Note:** Parameter retained for backward compatibility but has no effect
+
+### Breaking Change ⚠️
+
+**Parameter default changed:** `download_file(allow_insecure_ssl_fallback=False)` (was `True`)
+
+**Impact:** Code that relied on automatic SSL verification downgrade will now raise exceptions 
+for certificate errors. This is intentional security hardening.
+
+**Migration Guide:**
+- If you encounter SSL certificate errors, do NOT disable verification
+- For self-signed certificates: Add them to your system's CA certificate store
+- For development/testing: Use proper certificate configuration instead of bypassing verification
+- The `allow_insecure_ssl_fallback` parameter is now deprecated and ignored
+
+## ✅ Testing
+
+### Test Coverage
+- **13 new SSL verification tests** in `tests/unit/test_io_ssl_verification.py`
+- **SSL error handling tests** in `tests/unit/test_io_download_file.py`
+- All existing download tests updated and passing
+
+### Test Results
+- ✅ SSL errors raise immediately without retry
+- ✅ HTTPS downloads with valid certificates work correctly
+- ✅ HTTP (non-encrypted) URLs continue to work
+- ✅ Both `download_image_by_url()` and `download_file()` enforce SSL verification
+- ✅ Deprecated parameter is properly ignored
+
+## 📝 Documentation Updates
+
+### Updated Documentation
+1. **`download_file()`** - Parameter documentation updated to indicate deprecation
+2. **`download_dashboard()`** - Parameter documentation updated to indicate deprecation
+3. **Test files** - Include references to Issue #9446 with detailed explanations
+
+### Parameter Documentation
+```python
+allow_insecure_ssl_fallback: Deprecated parameter, ignored. SSL certificate
+    verification is always enforced for security.
+```
+
+## 🔍 Security Considerations
+
+### Why This Fix Matters
+1. **Prevents MITM Attacks:** Ensures all HTTPS connections verify server identity
+2. **No Silent Failures:** SSL errors are visible and must be handled explicitly
+3. **Defense in Depth:** Removes automatic fallback to insecure mode
+4. **Compliance:** Aligns with security best practices and standards
+
+### Affected Code Paths
+- Dashboard downloads from official repositories
+- Plugin downloads
+- Image downloads from external URLs
+- Any code using `download_file()` or `download_image_by_url()`
+
+## 📋 Checklist
+
+- [x] Security vulnerability fixed
+- [x] Breaking change documented
+- [x] All tests passing (13 new SSL tests added)
+- [x] Documentation updated for affected functions
+- [x] Migration guide provided
+- [x] No new dependencies introduced
+- [x] Code reviewed for security implications
+
+## 🔗 Related
+
+- Issue: #9446
+- Related commits: `218e88755` (earlier SSL error handling work)
+- Security: High priority - MITM vulnerability