M7: touch + outbound /state POST to Scrypted

state_client.{h,c}:
- Worker task drains a depth-1 queue (xQueueOverwrite gives the
  replace-on-full semantics from the spec — in-flight POST is never
  cancelled; the next queued entry is overwritten by newer state).
- esp_http_client POST to <scrypted>/state with Content-Type application/
  json, User-Agent ScryptedViewport/<version>, Connection: close, 1s
  timeout. Body: {"viewport":"<name>","state":"wake"|"sleep"}.
- Any non-2xx or transport error increments state_post_failures and is
  otherwise ignored. Silently drops if no Scrypted URL is configured.

touch.{h,c}:
- FT5426 capacitive touch on the shared I2C bus at 0x38.
- 30ms polling task; tracks down/up transitions, detects taps as
  down-then-up within 500ms with a 150ms debounce.
- On tap, toggles wake/sleep via state_machine_set_local(), which drives
  the local transition AND fires state_client_post() at Scrypted.

state_machine adds state_machine_set_local(): runs the same transition
as state_machine_set() then enqueues an outbound POST. Idle-timer
expiry now uses this path so Scrypted sees idle-driven sleeps too
(the spec's "tighten the race with /frame 409" path stays in place as
the fallback).

display.h exposes display_i2c_bus(); touch.c uses it instead of
re-initializing the same I2C port.

app_main starts state_client right after the state machine and starts
touch after display init (touch is skipped if display isn't up since
they share the bus).

CMakeLists.txt: add esp_http_client to REQUIRES.

Build clean against ESP-IDF 5.4 (binary ~860 KB; jumped ~210 KB from
M6 because esp_http_client + cJSON path pulls in tcp_transport, mbedtls,
http_parser).

TESTING.md M7: flask-based test receiver, tap dispatch verification,
failure-path check (kill receiver, confirm counter increments),
queue-coalescing behavior, no-POST-on-Scrypted-initiated, no-POST-
when-unconfigured.

1 files changed, 6 insertions, 0 deletions

diff --git a/main/display.h b/main/display.h
index e26845f..3119a60 100644
--- a/main/display.h
+++ b/main/display.h
@@ -4,6 +4,7 @@
 #include <stdint.h>
 
 #include "esp_err.h"
+#include "driver/i2c_master.h"
 
 // Initialize the panel-side MCU over I2C, then bring up the DSI link in
 // video (DPI) mode. Safe to call when the panel is not attached — returns
@@ -12,6 +13,11 @@ esp_err_t display_init(void);
 
 bool      display_is_up(void);
 
+// The Hosyond's I2C bus carries both the panel-MCU (0x45) and the touch
+// IC (0x38). Display owns the bus; touch shares it via this getter.
+// Returns NULL before display_init() succeeds.
+i2c_master_bus_handle_t display_i2c_bus(void);
+
 // 0–100, gamma-corrected to 0–255 on the panel-MCU PWM register.
 // brightness=0 is fully off (backlight enable line de-asserted).
 esp_err_t display_set_brightness(uint8_t brightness_0_100);