Wire the real fetch -> display -> deep-sleep cycle

frame_client_run() now does what it was always meant to: probe the tools
server, GET /frame/image and stream the response straight into the panel
via epd_display_stream() (esp_http_client's manual open/fetch_headers/read
API pulls in exactly the shape epd_display_stream()'s read_fn expects, so
the ~192KB frame never sits in RAM at once), then epd_sleep() and
esp_deep_sleep_start() for an hour.

Skips the WiFi/server status checklist screen on the happy path now that
there's a real photo to show instead -- three full refreshes every single
hour (status-pending, status-final, photo) wasn't worth it once bring-up
was actually working. Still shows it (status FAILED) when the server
isn't reachable, since nothing's been drawn yet that cycle and it's the
cheapest useful diagnostic. A mid-fetch failure after the panel's already
started refreshing just logs and retries sooner, rather than compounding
with a second refresh.

New Kconfig knobs: FRAME_FETCH_TIMEOUT_MS, FRAME_SLEEP_INTERVAL_S
(default 3600s), FRAME_RETRY_INTERVAL_S (default 300s on failure).

firmware/main/Kconfig.projbuild

@@ -51,4 +51,29 @@ menu "ESPresso Frame Configuration"
             How long to wait for an HTTP response from the tools server
             when checking reachability on the post-connect status screen.
 
+    config FRAME_FETCH_TIMEOUT_MS
+        int "Image fetch HTTP timeout (ms)"
+        default 15000
+        help
+            How long to wait on the GET /frame/image request before giving
+            up. The server does real work per request (Immich download +
+            resize + dither), so this is longer than the reachability
+            check's timeout.
+
+    config FRAME_SLEEP_INTERVAL_S
+        int "Deep sleep interval between refreshes (seconds)"
+        default 3600
+        help
+            How long the device deep-sleeps between successful
+            fetch-and-display cycles. Lower this for bench testing so you
+            don't have to wait an hour per iteration.
+
+    config FRAME_RETRY_INTERVAL_S
+        int "Deep sleep interval after a failed cycle (seconds)"
+        default 300
+        help
+            How long the device deep-sleeps before retrying after the
+            server was unreachable or the fetch/display failed, instead of
+            waiting the full FRAME_SLEEP_INTERVAL_S.
+
 endmenu