fix(stm32): discover Arduino_Core_STM32 framework libraries (SPI, Wire, ...) (#203)

The STM32 orchestrator installs the STM32duino core but never walked
libraries/*/ to surface bundled libraries to sketches. Any sketch that
transitively included <SPI.h> (e.g. FastLED's STM32 fastspi path) failed
with "fatal error: SPI.h: No such file or directory" despite SPI living
right there in the cache.

Mirror PR #164's Teensy fix:

- Add a shared FrameworkLibrary model + discover_framework_libraries()
  walker in fbuild-packages, used by both TeensyCores and Stm32Cores.
- Extract the #include-scanning / transitive-closure resolver out of the
  Teensy orchestrator into crate::framework_libs so both platforms share
  one code path.
- Wire Stm32Cores::get_framework_libraries() +
  get_framework_library_include_dirs() into the STM32 orchestrator after
  SrcWrapper so the resolver picks up SPI/Wire/EEPROM/... on demand and
  their include dirs reach the sketch compile command.

Fixes #202

Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: zackees

crates/fbuild-build/src/framework_libs.rs

@@ -14,6 +14,7 @@ pub mod compiler;
 pub mod esp32;
 pub mod esp8266;
 pub mod flag_overlay;
+pub mod framework_libs;
 pub mod generic_arm;
 pub mod linker;
 pub mod nrf52;

crates/fbuild-build/src/lib.rs

@@ -20,6 +20,7 @@ use fbuild_core::{Platform, Result};
 use fbuild_packages::{Framework, Toolchain};
 
 use crate::compile_database::TargetArchitecture;
+use crate::framework_libs::resolve_framework_library_sources;
 use crate::generic_arm::{ArmCompiler, ArmLinker};
 use crate::pipeline;
 use crate::source_scanner::SourceCollection;
@@ -103,6 +104,22 @@ impl BuildOrchestrator for Stm32Orchestrator {
                 .extend(scanner.scan_core_sources(&srcwrapper_src));
         }
 
+        // Walk Arduino_Core_STM32's libraries/ (SPI, Wire, EEPROM, ...) and
+        // pull in any the sketch transitively #includes. Without this, sketches
+        // that include <SPI.h> fail with "No such file or directory" because
+        // STM32duino only exposes bundled libraries via this framework-level
+        // discovery (PlatformIO's LDF does the same for `framework = arduino`).
+        let framework_libs = framework.get_framework_libraries();
+        let framework_library_sources =
+            resolve_framework_library_sources(&framework_libs, &params.project_dir, &ctx.src_dir);
+        if !framework_library_sources.is_empty() {
+            tracing::info!(
+                "STM32 framework library sources added: {}",
+                framework_library_sources.len()
+            );
+            sources.core_sources.extend(framework_library_sources);
+        }
+
         tracing::info!(
             "sources: {} sketch, {} core, {} variant",
             sources.sketch_sources.len(),
@@ -173,6 +190,9 @@ impl BuildOrchestrator for Stm32Orchestrator {
         }
         include_dirs.push(ctx.src_dir.clone());
         pipeline::discover_project_includes(&params.project_dir, &mut include_dirs);
+        // Bundled framework library headers (SPI, Wire, EEPROM, ...) so
+        // sketches can `#include <SPI.h>` etc.
+        include_dirs.extend(framework.get_framework_library_include_dirs());
 
         // STM32duino system includes (CMSIS device, HAL drivers, etc.)
         let system_dir = framework.get_system_dir();