feat: Add auto-detect ESP chip via security info and improve test coverage

[gandarez]

• Refactor chip detection from magic-register-only approach to use GET_SECURITY_INFO command with ChipID fallback via readReg.
• Add security_info.go for parsing security info responses (12/20 byte variants) and security flag decoding.
• Expand protocol layer with securityInfo command support and improve test coverage across flasher, protocol, and security_info packages.

This PR is essential to get esp32c6 support in this PR

[deadprogram]

I was just able to do a little testing on my machine. With this PR, the auto-detection no longer works on esp8266 or esp32.

[deadprogram]

@gandarez with this patch to your PR, I was able to flash esp3266 as well as esp32s3 boards:

diff --git a/pkg/espflasher/flasher.go b/pkg/espflasher/flasher.go
index 136b86a..cd9eab8 100644
--- a/pkg/espflasher/flasher.go
+++ b/pkg/espflasher/flasher.go
@@ -256,30 +256,29 @@ synced:
 // detectChip identifies the connected ESP chip.
 func (f *Flasher) detectChip() (*chipDef, error) {
        si, err := f.readSecurityInfo()
-       if err != nil {
-               return nil, fmt.Errorf("detect chip: %w", err)
-       }
-
-       for _, def := range chipDefs {
-               if def.UsesMagicValue {
-                       continue
-               }
+       if err == nil {
+               for _, def := range chipDefs {
+                       if def.UsesMagicValue {
+                               continue
+                       }
 
-               if si.ChipID != nil && *si.ChipID == uint32(def.ImageChipID) {
-                       def.SecureDownloadMode = si.ParsedFlags.SecureDownloadEnable
-                       return def, nil
+                       if si.ChipID != nil && *si.ChipID == uint32(def.ImageChipID) {
+                               def.SecureDownloadMode = si.ParsedFlags.SecureDownloadEnable
+                               return def, nil
+                       }
                }
        }
 
-       var magic uint32
-
-       // Try to read the chip magic value to verify the chip type (ESP8266, ESP32, ESP32-S2)
-       magic, err = f.conn.readReg(chipDetectMagicRegAddr)
-       if err != nil {
+       // Otherwise, try to read the chip magic value to verify the chip type (ESP8266, ESP32, ESP32-S2)
+       magic, err := f.conn.readReg(chipDetectMagicRegAddr)
+       switch {
+       case err != nil && si != nil:
                // Only ESP32-S2 does not support chip id detection
                // and supports secure download mode
                chipDefs[ChipESP32S2].SecureDownloadMode = si.ParsedFlags.SecureDownloadEnable
                return chipDefs[ChipESP32S2], nil
+       case err != nil:
+               return nil, fmt.Errorf("detect chip: %w", err)
        }
 
        // Check magic value for older chips (ESP8266, ESP32, ESP32-S2)

[deadprogram]

@gandarez did you see my proposed patch to this PR? What do you think?

[gandarez]

@deadprogram wdyt the proposed changes in this commit? Idea is to log when read security fails and fall though.

[deadprogram]

@deadprogram wdyt the proposed changes in this commit? Idea is to log when read security fails and fall though.

Can you please add that to this PR so I can try it out?

[deadprogram]

@deadprogram wdyt the proposed changes in this commit? Idea is to log when read security fails and fall though.

Can you please add that to this PR so I can try it out?

I just saw you already did that. Trying again now...

[deadprogram]

@gandarez please see my small wording change. It does in fact appear to do what you were saying and worked on my esp8266 and esp32 boards, as well as esp32-s3.

[gandarez]

@deadprogram change made and commits squashed

[deadprogram]

Thank you very much for the additions @gandarez now merging...