fix(build): use Docker for cross-arch Linux compilation

When building Linux binaries with a different target architecture than
the host (e.g., arm64 on x86_64), use Docker-based cross-compilation
instead of native build. The native GCC cannot compile ARM64 assembly
on an x86_64 host.

Adds a third condition to the build task selection: target architecture
must match host architecture to use native build.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

v3/internal/commands/build_assets/linux/Taskfile.yml

@@ -17,8 +17,11 @@ tasks:
   build:
     summary: Builds the application for Linux
     cmds:
-      # Linux requires CGO - use Docker when cross-compiling from non-Linux OR when no C compiler is available
-      - task: '{{if and (eq OS "linux") (eq .HAS_CC "true")}}build:native{{else}}build:docker{{end}}'
+      # Linux requires CGO - use Docker when:
+      # 1. Cross-compiling from non-Linux, OR
+      # 2. No C compiler is available, OR
+      # 3. Target architecture differs from host architecture (cross-arch compilation)
+      - task: '{{if and (eq OS "linux") (eq .HAS_CC "true") (eq .TARGET_ARCH ARCH)}}build:native{{else}}build:docker{{end}}'
         vars:
           ARCH: '{{.ARCH}}'
           DEV: '{{.DEV}}'
@@ -26,6 +29,8 @@ tasks:
     vars:
       DEFAULT_OUTPUT: '{{.BIN_DIR}}/{{.APP_NAME}}'
       OUTPUT: '{{ .OUTPUT | default .DEFAULT_OUTPUT }}'
+      # Determine target architecture (defaults to host ARCH if not specified)
+      TARGET_ARCH: '{{.ARCH | default ARCH}}'
       # Check if a C compiler is available (gcc or clang)
       HAS_CC:
         sh: '(command -v gcc >/dev/null 2>&1 || command -v clang >/dev/null 2>&1) && echo "true" || echo "false"'