refactor: name release assets from the board's chip model

Review follow-up for #72.

- releaseAssetName() takes ConfigSettings::chipModel ("", "s3", "c3", "c6"),
  so GitOTA no longer keeps its own chip switch. C3 keeps its name for when
  the build comes back.
- hasFS is set only when this board's own LittleFS image is in the release.
  isFsAsset() is gone; it also matched the old unsuffixed littlefs.bin, which
  the updater no longer asks for.
- releaseAssetName() returns void: no caller checked the result and every
  name fits currentFile.
- Both manual-upload hints name this board's file.
- KNOWN_ISSUES: the "Main" install can't work, the repo holds no .bin files.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

src/Utils.h

@@ -86,12 +86,10 @@ heap_emit_t heapEmitTarget(uint8_t num, uint32_t sinceLastMs, uint32_t intervalM
 // update has proven itself: it has run for minUptimeMs and the network is
 // up.  Until then a reset rolls back to the previous firmware.
 bool otaProven(bool networkUp, unsigned long uptimeMs, unsigned long minUptimeMs);
-// A release asset's name: "SomfyController.<kind>.<chip>.bin", kind "ino" for
-// the firmware or "littlefs" for the web UI image, chip e.g. "esp32s3".  False
-// when it doesn't fit in size.
-bool releaseAssetName(char *buf, size_t size, const char *kind, const char *chip);
-// Whether a release asset is a LittleFS image, for any chip.
-bool isFsAsset(const char *name);
+// A release asset's name: "SomfyController.<kind>.esp32<chipModel>.bin", kind
+// "ino" for the firmware or "littlefs" for the web UI image, chipModel as in
+// ConfigSettings ("" for the ESP32, "s3", "c3", "c6").
+void releaseAssetName(char *buf, size_t size, const char *kind, const char *chipModel);
 // How well loop() keeps up: the passes it made per second and its longest
 // pass, over the window since the last memStatus broadcast.  Only the loop
 // task calls record(), rate(), maxUs() and publish().  publish() closes the