feat: add display UI with splash screen, dashboard, and RSSI sparkline

Implement full SSD1306 OLED display support:
- Splash screen on boot (1.5s) with project name, version, board
- Dashboard showing radio state, config, counters, RSSI/SNR
- RSSI history sparkline (64-sample ring buffer, 2px-wide bars)
- DisplayOn/DisplayOff host commands routed via dedicated channel
- Pure render functions against generic DrawTarget (no hardware coupling)
- Display on/off control bypasses radio task entirely

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

vendor/ident_case/.cargo-checksum.json

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vendor/ident_case/.cargo_vcs_info.json

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+{
+  "git": {
+    "sha1": "bf0d863e3006b40a0d923a81d7b2dd2db1136c2c"
+  }
+}

vendor/ident_case/.travis.yml

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+language: rust
+env:
+  - stable
+  - beta
+  - nightly

vendor/ident_case/CHANGELOG.md

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+## v1.0.1 - March 18, 2019
+- Add `LICENSE` file (#3)[https://github.com/TedDriggs/ident_case/issues/3]

vendor/ident_case/Cargo.toml

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+# THIS FILE IS AUTOMATICALLY GENERATED BY CARGO
+#
+# When uploading crates to the registry Cargo will automatically
+# "normalize" Cargo.toml files for maximal compatibility
+# with all versions of Cargo and also rewrite `path` dependencies
+# to registry (e.g. crates.io) dependencies
+#
+# If you believe there's an error in this file please file an
+# issue against the rust-lang/cargo repository. If you're
+# editing this file be aware that the upstream Cargo.toml
+# will likely look very different (and much more reasonable)
+
+[package]
+name = "ident_case"
+version = "1.0.1"
+authors = ["Ted Driggs <ted.driggs@outlook.com>"]
+description = "Utility for applying case rules to Rust identifiers."
+documentation = "https://docs.rs/ident_case/1.0.1"
+readme = "README.md"
+license = "MIT/Apache-2.0"
+repository = "https://github.com/TedDriggs/ident_case"
+[badges.travis-ci]
+repository = "TedDriggs/ident_case"

vendor/ident_case/LICENSE

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+MIT License
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

vendor/ident_case/README.md

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+[![Build Status](https://travis-ci.org/TedDriggs/ident_case.svg?branch=master)](https://travis-ci.org/TedDriggs/ident_case)
+
+Crate for manipulating case of identifiers in Rust programs.
+
+# Features
+* Supports `snake_case`, `lowercase`, `camelCase`, 
+  `PascalCase`, `SCREAMING_SNAKE_CASE`, and `kebab-case`
+* Rename variants, and fields
+
+# Examples
+```rust
+assert_eq!("helloWorld", RenameRule::CamelCase.apply_to_field("hello_world"));
+
+assert_eq!("i_love_serde", RenameRule::SnakeCase.apply_to_variant("ILoveSerde"));
+```

vendor/ident_case/src/lib.rs

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+//! Crate for changing case of Rust identifiers.
+//!
+//! # Features
+//! * Supports `snake_case`, `lowercase`, `camelCase`, 
+//!   `PascalCase`, `SCREAMING_SNAKE_CASE`, and `kebab-case`
+//! * Rename variants, and fields
+//! 
+//! # Examples
+//! ```rust
+//! use ident_case::RenameRule;
+//!
+//! assert_eq!("helloWorld", RenameRule::CamelCase.apply_to_field("hello_world"));
+//!
+//! assert_eq!("i_love_serde", RenameRule::SnakeCase.apply_to_variant("ILoveSerde"));
+//! ```
+
+// Copyright 2017 Serde Developers
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+use std::ascii::AsciiExt;
+use std::str::FromStr;
+
+use self::RenameRule::*;
+
+/// A casing rule for renaming Rust identifiers.
+#[derive(Debug, PartialEq, Eq, Clone, Copy)]
+pub enum RenameRule {
+    /// No-op rename rule.
+    None,
+    /// Rename direct children to "lowercase" style.
+    LowerCase,
+    /// Rename direct children to "PascalCase" style, as typically used for enum variants.
+    PascalCase,
+    /// Rename direct children to "camelCase" style.
+    CamelCase,
+    /// Rename direct children to "snake_case" style, as commonly used for fields.
+    SnakeCase,
+    /// Rename direct children to "SCREAMING_SNAKE_CASE" style, as commonly used for constants.
+    ScreamingSnakeCase,
+    /// Rename direct children to "kebab-case" style.
+    KebabCase,
+}
+
+impl RenameRule {
+    /// Change case of a `PascalCase` variant.
+    pub fn apply_to_variant<S: AsRef<str>>(&self, variant: S) -> String {
+        
+        let variant = variant.as_ref();
+        match *self {
+            None | PascalCase => variant.to_owned(),
+            LowerCase => variant.to_ascii_lowercase(),
+            CamelCase => variant[..1].to_ascii_lowercase() + &variant[1..],
+            SnakeCase => {
+                let mut snake = String::new();
+                for (i, ch) in variant.char_indices() {
+                    if i > 0 && ch.is_uppercase() {
+                        snake.push('_');
+                    }
+                    snake.push(ch.to_ascii_lowercase());
+                }
+                snake
+            }
+            ScreamingSnakeCase => SnakeCase.apply_to_variant(variant).to_ascii_uppercase(),
+            KebabCase => SnakeCase.apply_to_variant(variant).replace('_', "-"),
+        }
+    }
+
+    /// Change case of a `snake_case` field.
+    pub fn apply_to_field<S: AsRef<str>>(&self, field: S) -> String {
+        
+        let field = field.as_ref();
+        match *self {
+            None | LowerCase | SnakeCase => field.to_owned(),
+            PascalCase => {
+                let mut pascal = String::new();
+                let mut capitalize = true;
+                for ch in field.chars() {
+                    if ch == '_' {
+                        capitalize = true;
+                    } else if capitalize {
+                        pascal.push(ch.to_ascii_uppercase());
+                        capitalize = false;
+                    } else {
+                        pascal.push(ch);
+                    }
+                }
+                pascal
+            }
+            CamelCase => {
+                let pascal = PascalCase.apply_to_field(field);
+                pascal[..1].to_ascii_lowercase() + &pascal[1..]
+            }
+            ScreamingSnakeCase => field.to_ascii_uppercase(),
+            KebabCase => field.replace('_', "-"),
+        }
+    }
+}
+
+impl FromStr for RenameRule {
+    type Err = ();
+
+    fn from_str(rename_all_str: &str) -> Result<Self, Self::Err> {
+        match rename_all_str {
+            "lowercase" => Ok(LowerCase),
+            "PascalCase" => Ok(PascalCase),
+            "camelCase" => Ok(CamelCase),
+            "snake_case" => Ok(SnakeCase),
+            "SCREAMING_SNAKE_CASE" => Ok(ScreamingSnakeCase),
+            "kebab-case" => Ok(KebabCase),
+            _ => Err(()),
+        }
+    }
+}
+
+impl Default for RenameRule {
+    fn default() -> Self {
+        RenameRule::None
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::RenameRule::*;
+
+    #[test]
+    fn rename_variants() {
+        for &(original, lower, camel, snake, screaming, kebab) in
+            &[
+                ("Outcome", "outcome", "outcome", "outcome", "OUTCOME", "outcome"),
+                ("VeryTasty", "verytasty", "veryTasty", "very_tasty", "VERY_TASTY", "very-tasty"),
+                ("A", "a", "a", "a", "A", "a"),
+                ("Z42", "z42", "z42", "z42", "Z42", "z42"),
+            ] {
+            assert_eq!(None.apply_to_variant(original), original);
+            assert_eq!(LowerCase.apply_to_variant(original), lower);
+            assert_eq!(PascalCase.apply_to_variant(original), original);
+            assert_eq!(CamelCase.apply_to_variant(original), camel);
+            assert_eq!(SnakeCase.apply_to_variant(original), snake);
+            assert_eq!(ScreamingSnakeCase.apply_to_variant(original), screaming);
+            assert_eq!(KebabCase.apply_to_variant(original), kebab);
+        }
+    }
+
+    #[test]
+    fn rename_fields() {
+        for &(original, pascal, camel, screaming, kebab) in
+            &[
+                ("outcome", "Outcome", "outcome", "OUTCOME", "outcome"),
+                ("very_tasty", "VeryTasty", "veryTasty", "VERY_TASTY", "very-tasty"),
+                ("_leading_under", "LeadingUnder", "leadingUnder", "_LEADING_UNDER", "-leading-under"),
+                ("double__under", "DoubleUnder", "doubleUnder", "DOUBLE__UNDER", "double--under"),
+                ("a", "A", "a", "A", "a"),
+                ("z42", "Z42", "z42", "Z42", "z42"),
+            ] {
+            assert_eq!(None.apply_to_field(original), original);
+            assert_eq!(PascalCase.apply_to_field(original), pascal);
+            assert_eq!(CamelCase.apply_to_field(original), camel);
+            assert_eq!(SnakeCase.apply_to_field(original), original);
+            assert_eq!(ScreamingSnakeCase.apply_to_field(original), screaming);
+            assert_eq!(KebabCase.apply_to_field(original), kebab);
+        }
+    }
+}