CVE-2026-40494: SAIL has heap buffer overflow in TGA RLE decoder — raw packet path missing bounds check

SAIL is a cross-platform library for loading and saving images with support for animation, metadata, and ICC profiles. Prior to commit 45d48d1f2e8e0d73e80bc1fd5310cb57f4547302, the TGA codec's RLE decoder in `tga.c` has an asymmetric bounds check vulnerability. The run-packet path (line 297) correctly clamps the repeat count to the remaining buffer space, but the raw-packet path (line 305-311) has no equivalent bounds check. This allows writing up to 496 bytes of attacker-controlled data past the end of a heap buffer. Commit 45d48d1f2e8e0d73e80bc1fd5310cb57f4547302 patches the issue.