docs(tactility-app-dev): note device_get_* not exported; use device_find_* legacy API

Flashed 0.8.0-dev firmware exports device_find_* but not the newer device_get_*
out-param API. verify_symbols.py compares vs local firmware source and can pass
even when the flashed firmware differs — confirm on-device via serial
(/dev/cu.usbmodem*, 115200). Record the local extern-declare workaround.

.claude/skills/tactility-app-development/references/symbols.md

@@ -39,6 +39,12 @@ print(f"undef {len(undef)} missing {missing}")
 
 ### New missing from v2/v3/v4/v5 UI passes
 
+- `device_get_by_name`, `device_get_first_by_type` (out-param API) → **Not exported** on flashed 0.8.0-dev (verified via serial on .129: `E ELF: Can't find symbol device_get_by_name`). The firmware exports the **legacy** `device_find_by_name` / `device_find_first_by_type` instead. Gotcha: newer SDK/CDN headers declare only `device_get_*` (so `device_find_*` fails to compile), but the flashed firmware only exports `device_find_*` (so `device_get_*` fails at load). Fix: call the exported legacy `device_find_*` and declare them locally in the app source since the SDK header dropped them:
+  ```c
+  extern struct Device* device_find_by_name(const char* name);
+  extern struct Device* device_find_first_by_type(const struct DeviceType* type);
+  ```
+  Verify the ACTUAL load on-device via serial (`/dev/cu.usbmodem*`, 115200) — `verify_symbols.py` compares against local firmware source and can report 0 missing even when the flashed firmware's export table differs.
 - `lv_obj_set_style_bg_grad_color/dir/stop` → **Not exported** 0.8.0-dev. Gradient fails `missing symbol`. Use solid `0x0E0E14`.
 - `LV_OPA_95` → **Not defined** (only 0/10/20/30/40/50/60/70/80/90/100/COVER/TRANSP). Use `COVER` or `90`.
 - `lv_arc_create`, `lv_arc_set_range/value/bg_angles`, `lv_arc_get_value` → **Not exported on 0.7.0-dev**, added `dff93cb6 Add lv_arc.h symbols (#496)` after 0.7 release. Symptom blue modal `Error / Application failed to start: missing symbol / OK`, heap healthy ~31KB not OOM. Fix horizontal slide using `lv_slider_create` + `lv_indev_get_point/active`. See `book-browser.md`.

AGENTS.md

@@ -121,6 +121,7 @@ Keep app source as pure C (no `auto`, no lambdas in `.c`) or rename to `.cpp`.
 Tactility firmware exports symbols via `ESP_ELFSYM_EXPORT` / `DEFINE_MODULE_SYMBOL` in `firmware/Modules/lvgl-module/source/symbols.c`. If ELF references an unexported symbol → device modal `Error / Application failed to start: missing symbol`, heap still healthy (~31KB free) → NOT OOM.
 
 Known missing on 0.8.0-dev:
+- `device_get_by_name` / `device_get_first_by_type` (out-param API) → **Not exported** by flashed firmware; use legacy exported `device_find_by_name` / `device_find_first_by_type` (declare them locally — newer SDK headers dropped them). Gotcha: `verify_symbols.py` compares vs local firmware SOURCE and can pass even when the flashed firmware's export table differs — confirm on-device via serial (`/dev/cu.usbmodem*`, 115200): `E ELF: Can't find symbol X`.
 - `lv_font_montserrat_14/18` → use `lvgl_get_text_font(SMALL/DEFAULT/LARGE)` via `tactility/lvgl_fonts.h`
 - `lv_obj_set_style_bg_grad_color/dir/stop`, `LV_OPA_95/5`, `LV_SYMBOL_STAR` → use solid colors, COVER/90
 - `lv_obj_set_style_max_width` → use `LV_PCT(92)` fixed percents for gutters