feat(p4): brancher media_manager + /game/file sur /sdcard

- media_manager resolve_play_path : un chemin relatif préfère désormais
  /sdcard/music/<f> quand il existe (asset store SD), fallback LittleFS.
  Les chemins absolus (/sdcard/... | /littlefs/...) passent inchangés.
- /game/file : route le préfixe `sd/<…>` → /sdcard/<…> (≤8 Mio, exige la
  carte montée) en plus de `apps/<…>` → /littlefs/apps/ (≤256 Kio).
- sd_storage.h : include <stdint.h> (uint32_t).

Validé sur Freenove : POST /game/file?path=sd/music/cue440.wav → écrit sur
la microSD ; POST /game/media/play {path:"cue440.wav"} → résolu en
/sdcard/music/cue440.wav, 32000 B streamés en ~1005 ms au MAX98357A.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

idf_zacus/components/game_endpoint/CMakeLists.txt

@@ -16,6 +16,7 @@ idf_component_register(
         joltwallet__littlefs
         puzzle_state
         media_manager
+        sd_storage
     PRIV_REQUIRES
         local_puzzles
 )

idf_zacus/components/game_endpoint/game_endpoint.c

@@ -19,6 +19,7 @@
 #include "esp_littlefs.h"
 #include "esp_log.h"
 #include "media_manager.h"
+#include "sd_storage.h"
 #include "esp_system.h"
 #include "freertos/FreeRTOS.h"
 #include "freertos/task.h"
@@ -1001,22 +1002,36 @@ static esp_err_t handle_file_post(httpd_req_t *req) {
                               sizeof(path_param)) != ESP_OK) {
         return send_error(req, "400 Bad Request", "missing path param");
     }
-    if (strncmp(path_param, "apps/", 5) != 0 || strstr(path_param, "..") ||
+    // Route: apps/<…> → /littlefs/apps/<…> (display shell tiles, ≤256 KiB);
+    //        sd/<…>   → /sdcard/<…>        (P4 large assets: audio, images).
+    const bool to_sd   = (strncmp(path_param, "sd/", 3) == 0);
+    const bool to_apps = (strncmp(path_param, "apps/", 5) == 0);
+    if ((!to_sd && !to_apps) || strstr(path_param, "..") ||
         path_param[strlen(path_param) - 1] == '/') {
-        return send_error(req, "403 Forbidden", "path must be under apps/");
+        return send_error(req, "403 Forbidden", "path must be under apps/ or sd/");
     }
-    if (req->content_len <= 0 ||
-        req->content_len > GAME_ENDPOINT_MAX_FILE_BYTES) {
-        return send_error(req, "400 Bad Request", "size 1..262144 bytes");
-    }
-    if (mount_storage_lazy() != ESP_OK) {
-        return send_error(req, "503 Service Unavailable", "storage_unavailable");
+    const long max_bytes = to_sd ? (8L * 1024 * 1024) : GAME_ENDPOINT_MAX_FILE_BYTES;
+    if (req->content_len <= 0 || (long) req->content_len > max_bytes) {
+        return send_error(req, "400 Bad Request", "file too large");
     }
 
-    char full[160];
-    snprintf(full, sizeof(full), "/littlefs/%s", path_param);
+    char full[192];
+    size_t root_len;
+    if (to_sd) {
+        if (!sd_storage_ready()) {
+            return send_error(req, "503 Service Unavailable", "sd_not_mounted");
+        }
+        snprintf(full, sizeof(full), "/sdcard/%s", path_param + 3);  // strip "sd/"
+        root_len = strlen("/sdcard/");
+    } else {
+        if (mount_storage_lazy() != ESP_OK) {
+            return send_error(req, "503 Service Unavailable", "storage_unavailable");
+        }
+        snprintf(full, sizeof(full), "/littlefs/%s", path_param);
+        root_len = strlen("/littlefs/");
+    }
     // mkdir -p for intermediate directories.
-    for (char *p = full + strlen("/littlefs/"); *p; p++) {
+    for (char *p = full + root_len; *p; p++) {
         if (*p == '/') {
             *p = '\0';
             mkdir(full, 0775);   // EEXIST is fine

idf_zacus/components/media_manager/media_manager.c

@@ -158,10 +158,20 @@ static void resolve_play_path(char *out, size_t out_len, const char *path) {
         return;
     }
     if (path[0] == '/') {
-        copy_text(out, out_len, path);
-    } else {
-        snprintf(out, out_len, "%s/%s", s_media.config.music_dir, path);
+        copy_text(out, out_len, path);   // absolute: /sdcard/... or /littlefs/...
+        return;
     }
+    // Relative cue: prefer the microSD copy when present (P4 — large asset
+    // store), else fall back to the LittleFS music_dir. file_exists() returns
+    // false when no card is mounted, so this is transparent without a hard
+    // dependency on sd_storage.
+    char sd_try[MEDIA_PATH_MAX];
+    snprintf(sd_try, sizeof(sd_try), "/sdcard/music/%s", path);
+    if (file_exists(sd_try)) {
+        copy_text(out, out_len, sd_try);
+        return;
+    }
+    snprintf(out, out_len, "%s/%s", s_media.config.music_dir, path);
 }
 
 static void sanitize_filename(char *out, size_t out_len,

idf_zacus/components/sd_storage/sd_storage.h

@@ -8,6 +8,7 @@
 #pragma once
 
 #include <stdbool.h>
+#include <stdint.h>
 #include "esp_err.h"
 
 #ifdef __cplusplus