feat: Complete Rust port of WiFi-DensePose with modular crates

Major changes:
- Organized Python v1 implementation into v1/ subdirectory
- Created Rust workspace with 9 modular crates:
  - wifi-densepose-core: Core types, traits, errors
  - wifi-densepose-signal: CSI processing, phase sanitization, FFT
  - wifi-densepose-nn: Neural network inference (ONNX/Candle/tch)
  - wifi-densepose-api: Axum-based REST/WebSocket API
  - wifi-densepose-db: SQLx database layer
  - wifi-densepose-config: Configuration management
  - wifi-densepose-hardware: Hardware abstraction
  - wifi-densepose-wasm: WebAssembly bindings
  - wifi-densepose-cli: Command-line interface

Documentation:
- ADR-001: Workspace structure
- ADR-002: Signal processing library selection
- ADR-003: Neural network inference strategy
- DDD domain model with bounded contexts

Testing:
- 69 tests passing across all crates
- Signal processing: 45 tests
- Neural networks: 21 tests
- Core: 3 doc tests

Performance targets:
- 10x faster CSI processing (~0.5ms vs ~5ms)
- 5x lower memory usage (~100MB vs ~500MB)
- WASM support for browser deployment

rust-port/wifi-densepose-rs/crates/wifi-densepose-core/Cargo.toml

@@ -0,0 +1,64 @@
+[package]
+name = "wifi-densepose-core"
+description = "Core types, traits, and utilities for WiFi-DensePose pose estimation system"
+version.workspace = true
+edition.workspace = true
+authors.workspace = true
+license.workspace = true
+repository.workspace = true
+documentation.workspace = true
+keywords.workspace = true
+categories.workspace = true
+readme = "README.md"
+
+[features]
+default = ["std"]
+std = []
+serde = ["dep:serde", "ndarray/serde"]
+async = ["dep:async-trait"]
+
+[dependencies]
+# Error handling
+thiserror.workspace = true
+
+# Serialization (optional)
+serde = { workspace = true, optional = true }
+
+# Numeric types
+ndarray.workspace = true
+num-complex.workspace = true
+num-traits.workspace = true
+
+# Async traits (optional)
+async-trait = { version = "0.1", optional = true }
+
+# Time handling
+chrono = { version = "0.4", features = ["serde"] }
+
+# UUID for unique identifiers
+uuid = { version = "1.6", features = ["v4", "serde"] }
+
+[dev-dependencies]
+serde_json.workspace = true
+proptest.workspace = true
+
+[lints.rust]
+unsafe_code = "forbid"
+missing_docs = "warn"
+
+[lints.clippy]
+all = "warn"
+pedantic = "warn"
+nursery = "warn"
+# Allow specific lints that are too strict for this crate
+missing_const_for_fn = "allow"
+doc_markdown = "allow"
+module_name_repetitions = "allow"
+must_use_candidate = "allow"
+cast_precision_loss = "allow"
+redundant_closure_for_method_calls = "allow"
+suboptimal_flops = "allow"
+imprecise_flops = "allow"
+manual_midpoint = "allow"
+unnecessary_map_or = "allow"
+missing_panics_doc = "allow"