[feat] implement backend abstraction, dynamic backend selection, and GPU feature integration

crates/polyscribe-core/Cargo.toml

@@ -0,0 +1,32 @@
+[package]
+name = "polyscribe"
+version = "0.1.0"
+edition = "2024"
+license = "MIT"
+
+[features]
+# Default: CPU only; no GPU features enabled
+default = []
+# GPU backends map to whisper-rs features or FFI stub for Vulkan
+gpu-cuda = ["whisper-rs/cuda"]
+gpu-hip = ["whisper-rs/hipblas"]
+gpu-vulkan = []
+# explicit CPU fallback feature (no effect at build time, used for clarity)
+cpu-fallback = []
+
+[dependencies]
+anyhow = "1.0.98"
+serde = { version = "1.0.219", features = ["derive"] }
+serde_json = "1.0.142"
+toml = "0.8"
+chrono = { version = "0.4", features = ["clock"] }
+sha2 = "0.10"
+whisper-rs = { git = "https://github.com/tazz4843/whisper-rs" }
+libc = "0.2"
+cliclack = "0.3"
+indicatif = "0.17"
+thiserror = "1"
+directories = "5"
+
+[build-dependencies]
+# no special build deps