Migrate to IDF 5.5.3 candidate

Pin PlatformIO packages and toolchains, rebase protected SDK
overrides, and add WebSocket receive regression coverage. Document
isolated candidate validation, archive provenance, and remaining gates.

third_party/release-notices/inputs.json

@@ -279,8 +279,8 @@
         122
       ],
       "root": "sdk",
-      "sha256": "09210c5a601647ca5775d127a2951bab2f3e509192b53487bbea8a93d8731b78",
-      "size": 50176
+      "sha256": "edc39052244526cb91c93a16bc765194031060e5560fd432e75542f2f6c8db53",
+      "size": 54323
     },
     {
       "output_sha256": "cfc7749b96f63bd31c3c42b5c471bf756814053e847c10f3eb003417bc523d30",
@@ -300,7 +300,7 @@
         124
       ],
       "root": "sdk",
-      "sha256": "6bba77064aaa68a06f8d4c01432064a1b050c91ed22741c547785b0d8a6c07d8",
+      "sha256": "db7fbbb322bccb4a21bc1607208a6bb7d1f4c0d7ecc3299de10c9e60edaa943b",
       "size": 42937
     },
     {
@@ -312,8 +312,8 @@
         123
       ],
       "root": "sdk",
-      "sha256": "6481942b62e51125e2a43441fa0900cbda74bd2ea05c82f0c29eb4933c31946e",
-      "size": 15257
+      "sha256": "a2a5ca0549fbe8d1ddd7f9647a48a31fdd6329b997e1550ab69d6a10efecff0d",
+      "size": 15459
     },
     {
       "output_sha256": "cfc7749b96f63bd31c3c42b5c471bf756814053e847c10f3eb003417bc523d30",
@@ -355,7 +355,7 @@
       "size": 1036
     },
     {
-      "output_sha256": "8e3d9f79bbbdf6dfd6fbf132982a7ec3a45ff6dac92277034316efae4cccad84",
+      "output_sha256": "e53c9bcefd4327c713696e870a3568a27cedf8833467b9cd9536cb2e09ab7ad8",
       "path": "components/freertos/FreeRTOS-Kernel/include/freertos/task.h",
       "purpose": "Original opening attribution/license comment(s), exact full-source hash and excerpt",
       "range": [
@@ -363,8 +363,8 @@
         1455
       ],
       "root": "sdk",
-      "sha256": "ac666bcbe4acb21c44cc820631f8c579d089698967015054c5ab42d092dddc2d",
-      "size": 133072
+      "sha256": "8b908b964d2c87377838762478253eec04312b985e6bb680bacd3f03ab253897",
+      "size": 133108
     },
     {
       "output_sha256": "968c3f0d60fb9ee8cc1047503823e75ccc28bf6e7e7b0451894b01c1e400d939",
@@ -465,8 +465,8 @@
         223
       ],
       "root": "sdk",
-      "sha256": "b726c0c55bc5f32255f129d55f9f2fface85ce83de90a2d16c9017b93b738bff",
-      "size": 329921
+      "sha256": "0154e70f20b465213d3f97a9c2b75e686d79ee83592f90e1d7e7d995593ca7e1",
+      "size": 336963
     },
     {
       "output_sha256": "0664aa34d3da2b71799883b2fc3250286f76ee69ed0b3676d53d25b635ee721d",
@@ -477,8 +477,8 @@
         169
       ],
       "root": "sdk",
-      "sha256": "fd399239aee30384786a19b47bfe5dd22b979d5d89bb38f29f0c82a3d81daaf7",
-      "size": 19803
+      "sha256": "55edce5b8fcb039a404b84ea830f06d018128b155dfbf0d74d26b17247b546c6",
+      "size": 19934
     },
     {
       "output_sha256": "20ed622a5f1a273258b415097609f6a236fb2f23f8c593c63e29e6cc77de0032",
@@ -547,30 +547,30 @@
       "size": 64919
     },
     {
-      "output_sha256": "1cc05e4ea172de6be2e6b961994de42a0f7433406619f6474811b11066718908",
+      "output_sha256": "230c52993499adf9f64d1d6477495ea46c3f14d63022bd52081858373098da68",
       "path": "package.json",
-      "purpose": "Installed SDK package 3.50500.0 identity",
+      "purpose": "Installed SDK package 3.50503.0 identity",
       "range": null,
       "root": "sdk",
-      "sha256": "1cc05e4ea172de6be2e6b961994de42a0f7433406619f6474811b11066718908",
+      "sha256": "230c52993499adf9f64d1d6477495ea46c3f14d63022bd52081858373098da68",
       "size": 536
     },
     {
-      "output_sha256": "6474d3ae428762830d36e3b179c6e1622f8f5dc7d32ea94f47be9c122c467979",
+      "output_sha256": "b473c8e2ed91b38d7e96e54d4ce094474ca6015c0641b7cdfc0ab94b1f8b4668",
       "path": "version.txt",
-      "purpose": "Installed IDF 5.5.0 identity",
+      "purpose": "Installed IDF 5.5.3 identity",
       "range": null,
       "root": "sdk",
-      "sha256": "6474d3ae428762830d36e3b179c6e1622f8f5dc7d32ea94f47be9c122c467979",
+      "sha256": "b473c8e2ed91b38d7e96e54d4ce094474ca6015c0641b7cdfc0ab94b1f8b4668",
       "size": 5
     },
     {
-      "output_sha256": "dd464ff1928a475656430e04342a94f0293d2aaf4447bdae438a69c7accc1698",
+      "output_sha256": "bdd3b852d051d6513912e71d29851bd04b800e2d33d78aec48067af5d83da5c9",
       "path": "package.json",
-      "purpose": "Installed Xtensa toolchain 14.2.0+20241119 identity; not runtime license classification",
+      "purpose": "Installed Xtensa toolchain 14.2.0+20251107 identity; not runtime license classification",
       "range": null,
       "root": "toolchain",
-      "sha256": "dd464ff1928a475656430e04342a94f0293d2aaf4447bdae438a69c7accc1698",
+      "sha256": "bdd3b852d051d6513912e71d29851bd04b800e2d33d78aec48067af5d83da5c9",
       "size": 472
     },
     {
@@ -720,7 +720,7 @@
   ],
   "schema": 1,
   "snapshot": {
-    "idf": "5.5.0",
+    "idf": "5.5.3",
     "managed": {
       "espressif__esp_tinyusb": "2.2.1",
       "espressif__led_strip": "3.0.3",
@@ -729,8 +729,8 @@
       "wolfssl__wolfssh": "1.4.20",
       "wolfssl__wolfssl": "5.8.2~1"
     },
-    "reviewed": "2026-09-16",
-    "sdk_package": "3.50500.0",
-    "toolchain_package": "14.2.0+20241119"
+    "reviewed": "2026-09-18",
+    "sdk_package": "3.50503.0",
+    "toolchain_package": "14.2.0+20251107"
   }
 }