unified end-to-end per-frame instrumentation + version stamps

Cross-side timing was opaque: script saw "req=70ms" but couldn't
split TCP/dispatch overhead from firmware decode time, and firmware
serial logs and Scrypted console logs couldn't be correlated.

Firmware /frame handler now emits Server-Timing on every response
with per-stage breakdown:
  Server-Timing: recv;dur=X, dec;dur=Y, paint;dur=Z,
                 post;dur=W, handle;dur=total
Script parses it, joins by X-Frame-Seq implicitly (one POST per seq),
derives net_up = req − fw_total, and logs a multi-line p50/p95
breakdown every 10 fetches:

  fetch "kitchen" #10 (jpeg=137KB)
     wall      p50=65ms  p95=140ms
     emit→post p50=0ms   p95=2ms      (queue wait)
     req       p50=62ms  p95=135ms    (fetch → Response headers)
       net_up  p50=43ms  p95=110ms    (TCP + body wire + dispatch)
       fw_recv p50=12ms  p95=18ms     (body off the wire)
       fw_dec  p50=6ms   p95=8ms      (hardware JPEG)
       fw_paint p50=0.1ms p95=0.2ms   (backbuffer flip)
       fw_post p50=0.4ms p95=0.6ms
     body-read p50=1ms                 (drain — empty body)
     inflight  d0=8 d1=2 d2=0
     stale-drops=0

Plus version stamps on both sides for the "is the user on the right
code" question:
- CMakeLists: PROJECT_VER = git short hash + -dirty marker if dirty.
  esp_app_get_description()->version exposes it at runtime. Boot
  log: "Scrypted Viewport boot (v0.1.0 build=4cf36e2-dirty)".
- TS: SCRIPT_VERSION const at the top, bumped per commit, logged at
  script-eval: "Scrypted Viewport up (script=4cf36e2). Callback ..."

2 files changed, 23 insertions, 1 deletions

diff --git a/main/app_main.c b/main/app_main.c
index a60496d..00a77bb 100644
--- a/main/app_main.c
+++ b/main/app_main.c
@@ -10,6 +10,7 @@
 #include "touch.h"
 #include "viewport_state.h"
 
+#include "esp_app_desc.h"
 #include "esp_event.h"
 #include "esp_log.h"
 #include "esp_netif.h"
@@ -39,7 +40,12 @@ void app_main(void)
 
     viewport_state_init();
     nvs_config_load();  // apply persisted config over defaults (best-effort)
-    ESP_LOGI(TAG, "Scrypted Viewport boot (v%s)", VIEWPORT_VERSION);
+    // PROJECT_VER comes from CMakeLists.txt — git short hash + dirty
+    // marker. Logged in the very first line so any captured boot log
+    // tells us exactly which build is running.
+    const esp_app_desc_t *desc = esp_app_get_description();
+    ESP_LOGI(TAG, "Scrypted Viewport boot (v%s build=%s)",
+             VIEWPORT_VERSION, desc ? desc->version : "?");
 
     // ------------------------------------------------------------------
     // Networking. Driver starts even with no cable plugged in; we just
diff --git a/main/http_api.c b/main/http_api.c
index c490a85..69e555e 100644
--- a/main/http_api.c
+++ b/main/http_api.c
@@ -499,6 +499,22 @@ static esp_err_t frame_post_handler(httpd_req_t *req)
 
     state_machine_frame_painted();  // reset idle timer
 
+    // Server-Timing per-stage breakdown so the Scrypted side can build
+    // a unified end-to-end trace per frame (joined by X-Frame-Seq).
+    // Units are ms with 0.1ms precision — paint is sub-millisecond
+    // so the decimal matters there. Scrypted subtracts the sum from
+    // its own (fetch_start → Response_headers) measurement to derive
+    // the network up + handler-dispatch overhead it can't see directly.
+    char st_hdr[160];
+    snprintf(st_hdr, sizeof(st_hdr),
+             "recv;dur=%.1f, dec;dur=%.1f, paint;dur=%.1f, post;dur=%.1f, handle;dur=%.1f",
+             (t_recv   - t_first_byte) / 1000.0,
+             (t_decode - t_recv)       / 1000.0,
+             (t_paint  - t_decode)     / 1000.0,
+             (t_post   - t_paint)      / 1000.0,
+             (t_post   - t_entry)      / 1000.0);
+    httpd_resp_set_hdr(req, "Server-Timing", st_hdr);
+
     httpd_resp_set_status(req, "204 No Content");
     return httpd_resp_send(req, NULL, 0);
 }