feat: local Nostr relay with relay selection, sync, and integration tests

Local Nostr relay (NIP-01) on port 4869 with LittleFS 4MB storage.
All events published locally first, then synced to public relays via REQ-diff.
Relay selection via NIP-11 HTTP probing with NIP-77 scoring and auto-failover.

Components:
- wisp_relay: 16-file local relay (ws_server, storage_engine, sub_manager,
  broadcaster, relay_validator, router, handlers, rate_limiter, nip11,
  deletion, flash_monitor, relay_types)
- esp_littlefs: LittleFS VFS integration (git submodule)
- negentropy: for future NIP-77 binary sync (git submodule)

New source files:
- local_relay.c/h: thin wrapper for relay init/start/publish
- relay_selector.c/h: NIP-11 probe + scoring + auto-failover
- sync_manager.c/h: REQ-diff sync (primary 30min, fallback 6h)

Bug fixes:
- config.c: use-after-free (cJSON_Delete before seed_relays/sync parsing)
- local_relay: moved init to app_main for boot-time start (not gated on STA IP)

Flash layout: 4MB LittleFS partition at 0x500000 for relay_store

Test results (Board B, live hardware):
- Smoke: ping + HTTP 4869 + NIP-11: PASS
- NIP-11 info document: 10/11 PASS
- WS pub/sub (connect, REQ/EOSE, EVENT/OK, CLOSE, concurrent): 6/6 PASS
- Unit tests (relay_validator + relay_selector): 13/13 PASS

Hardware test make targets in physical-router-test-automation/:
- make relay-build, relay-flash-b, relay-test-smoke/nip11/pubsub/sync/full

1 files changed, 85 insertions, 0 deletions

diff --git a/components/qrcode/include/qrcoded.h b/components/qrcode/include/qrcoded.h
new file mode 100755
index 0000000..602f9c0
--- /dev/null
+++ b/components/qrcode/include/qrcoded.h
@@ -0,0 +1,85 @@
+/**
+ * The MIT License (MIT)
+ *
+ * This library is written and maintained by Richard Moore.
+ * Major parts were derived from Project Nayuki's library.
+ *
+ * Copyright (c) 2017 Richard Moore     (https://github.com/ricmoo/QRCode)
+ * Copyright (c) 2017 Project Nayuki    (https://www.nayuki.io/page/qr-code-generator-library)
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+/**
+ *  Special thanks to Nayuki (https://www.nayuki.io/) from which this library was
+ *  heavily inspired and compared against.
+ *
+ *  See: https://github.com/nayuki/QR-Code-generator/tree/master/cpp
+ */
+
+#ifndef __QRCODE_H_
+#define __QRCODE_H_
+
+#include <stdbool.h>
+#include <stdint.h>
+
+// QR Code Format Encoding
+#define MODE_NUMERIC 0
+#define MODE_ALPHANUMERIC 1
+#define MODE_BYTE 2
+
+// Error Correction Code Levels
+#define ECC_LOW 0
+#define ECC_MEDIUM 1
+#define ECC_QUARTILE 2
+#define ECC_HIGH 3
+
+// If set to non-zero, this library can ONLY produce QR codes at that version
+// This saves a lot of dynamic memory, as the codeword tables are skipped
+#ifndef LOCK_VERSION
+#define LOCK_VERSION 0
+#endif
+
+typedef struct QRCode
+{
+    uint8_t version;
+    uint8_t size;
+    uint8_t ecc;
+    uint8_t mode;
+    uint8_t mask;
+    uint8_t *modules;
+} QRCode;
+
+#ifdef __cplusplus
+extern "C"
+{
+#endif /* __cplusplus */
+
+    uint16_t qrcode_getBufferSize(uint8_t version);
+
+    int8_t qrcode_initText(QRCode *qrcoded, uint8_t *modules, uint8_t version, uint8_t ecc, const char *data);
+    int8_t qrcode_initBytes(QRCode *qrcoded, uint8_t *modules, uint8_t version, uint8_t ecc, uint8_t *data, uint16_t length);
+
+    bool qrcode_getModule(QRCode *qrcoded, uint8_t x, uint8_t y);
+
+#ifdef __cplusplus
+}
+#endif /* __cplusplus */
+
+#endif /* __QRCODE_H_ */