fix: make agent-build.instructions.md visible to agent mode; fix cpp.instructions.md glob whitespace

Agent-Logs-Url: https://github.com/MoonModules/WLED-MM/sessions/cc079927-b059-4d79-9290-886ef72964c8

Co-authored-by: softhack007 <91616163+softhack007@users.noreply.github.com>

.github/agent-build.instructions.md

@@ -1,3 +1,6 @@
+---
+applyTo: "**"
+---
 # Agent-Mode Build & Test Instructions
 
 Detailed build workflow, timeouts, and troubleshooting for making code changes in agent mode. Always reference these instructions first when running builds or validating changes.

.github/copilot-instructions.md

@@ -44,7 +44,7 @@ Always reference these instructions first and fallback to search or bash command
 **Build firmware to validate code changes**: `pio run -e esp32_4MB_V4_M` — must succeed, never skip this step.
 Common firmware environments: `esp32_4MB_V4_M`, `esp32_16MB_V4_S_HUB75`, `esp32S3_8MB_PSRAM_M_qspi`, `esp32_16MB_V4_M_eth`, `esp32dev_compat`, `esp8266_4MB_S` (deprecated)
 
-For detailed build timeouts, development workflows, troubleshooting, and validation steps, see [agent-build-instructions.md](agent-build-instructions.md).
+For detailed build timeouts, development workflows, troubleshooting, and validation steps, see [agent-build.instructions.md](agent-build.instructions.md).
 
 ## Repository Structure
 

.github/cpp.instructions.md

@@ -1,5 +1,5 @@
 ---
-applyTo: "**/*.cpp,**/*.h,**/*.hpp, **/*.ino"
+applyTo: "**/*.cpp,**/*.h,**/*.hpp,**/*.ino"
 ---
 # C++ Coding Conventions