[esp] Add Rust no-std example.

esp/rust/03_no-std-lcd/Cargo.toml

@@ -0,0 +1,49 @@
+[package]
+name = "esp-idf-no-std"
+version = "0.1.0"
+authors = ["Shaun Reed <shaunrd0@gmail.com>"]
+edition = "2021"
+resolver = "2"
+rust-version = "1.77"
+
+[[bin]]
+name = "esp-idf-no-std"
+harness = false # do not use the built in cargo test harness -> resolve rust-analyzer errors
+
+[profile.release]
+opt-level = "s"
+
+[profile.dev]
+debug = true    # Symbols are nice and they don't increase the size on Flash
+opt-level = "z"
+
+[features]
+default = []
+
+experimental = ["esp-idf-svc/experimental"]
+
+[dependencies]
+log = "0.4"
+esp-idf-svc = "0.51"
+esp-idf-hal = "0.45.2"
+anyhow = "1.0.98"
+
+# --- Optional Embassy Integration ---
+# esp-idf-svc = { version = "0.51", features = ["critical-section", "embassy-time-driver", "embassy-sync"] }
+
+# If you enable embassy-time-driver, you MUST also add one of:
+
+# a) Standalone Embassy libs ( embassy-time, embassy-sync etc) with a foreign async runtime:
+# embassy-time = { version = "0.4.0", features = ["generic-queue-8"] } # NOTE: any generic-queue variant will work
+
+# b) With embassy-executor:
+# embassy-executor = { version = "0.7", features = ["executor-thread", "arch-std"] }
+
+# NOTE: if you use embassy-time with embassy-executor you don't need the generic-queue-8 feature
+
+# --- Temporary workaround for embassy-executor < 0.8 ---
+# esp-idf-svc = { version = "0.51", features = ["embassy-time-driver", "embassy-sync"] }
+# critical-section = { version = "1.1", features = ["std"], default-features = false }
+
+[build-dependencies]
+embuild = "0.33"