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/syn-1.0.109/tests/test_meta.rs

@@ -0,0 +1,378 @@
+#![allow(clippy::shadow_unrelated, clippy::too_many_lines)]
+
+#[macro_use]
+mod macros;
+
+use syn::{Meta, MetaList, MetaNameValue, NestedMeta};
+
+#[test]
+fn test_parse_meta_item_word() {
+    let input = "hello";
+
+    snapshot!(input as Meta, @r###"
+    Path(Path {
+        segments: [
+            PathSegment {
+                ident: "hello",
+                arguments: None,
+            },
+        ],
+    })
+    "###);
+}
+
+#[test]
+fn test_parse_meta_name_value() {
+    let input = "foo = 5";
+    let (inner, meta) = (input, input);
+
+    snapshot!(inner as MetaNameValue, @r###"
+    MetaNameValue {
+        path: Path {
+            segments: [
+                PathSegment {
+                    ident: "foo",
+                    arguments: None,
+                },
+            ],
+        },
+        lit: 5,
+    }
+    "###);
+
+    snapshot!(meta as Meta, @r###"
+    Meta::NameValue {
+        path: Path {
+            segments: [
+                PathSegment {
+                    ident: "foo",
+                    arguments: None,
+                },
+            ],
+        },
+        lit: 5,
+    }
+    "###);
+
+    assert_eq!(meta, inner.into());
+}
+
+#[test]
+fn test_parse_meta_name_value_with_keyword() {
+    let input = "static = 5";
+    let (inner, meta) = (input, input);
+
+    snapshot!(inner as MetaNameValue, @r###"
+    MetaNameValue {
+        path: Path {
+            segments: [
+                PathSegment {
+                    ident: "static",
+                    arguments: None,
+                },
+            ],
+        },
+        lit: 5,
+    }
+    "###);
+
+    snapshot!(meta as Meta, @r###"
+    Meta::NameValue {
+        path: Path {
+            segments: [
+                PathSegment {
+                    ident: "static",
+                    arguments: None,
+                },
+            ],
+        },
+        lit: 5,
+    }
+    "###);
+
+    assert_eq!(meta, inner.into());
+}
+
+#[test]
+fn test_parse_meta_name_value_with_bool() {
+    let input = "true = 5";
+    let (inner, meta) = (input, input);
+
+    snapshot!(inner as MetaNameValue, @r###"
+    MetaNameValue {
+        path: Path {
+            segments: [
+                PathSegment {
+                    ident: "true",
+                    arguments: None,
+                },
+            ],
+        },
+        lit: 5,
+    }
+    "###);
+
+    snapshot!(meta as Meta, @r###"
+    Meta::NameValue {
+        path: Path {
+            segments: [
+                PathSegment {
+                    ident: "true",
+                    arguments: None,
+                },
+            ],
+        },
+        lit: 5,
+    }
+    "###);
+
+    assert_eq!(meta, inner.into());
+}
+
+#[test]
+fn test_parse_meta_item_list_lit() {
+    let input = "foo(5)";
+    let (inner, meta) = (input, input);
+
+    snapshot!(inner as MetaList, @r###"
+    MetaList {
+        path: Path {
+            segments: [
+                PathSegment {
+                    ident: "foo",
+                    arguments: None,
+                },
+            ],
+        },
+        nested: [
+            Lit(5),
+        ],
+    }
+    "###);
+
+    snapshot!(meta as Meta, @r###"
+    Meta::List {
+        path: Path {
+            segments: [
+                PathSegment {
+                    ident: "foo",
+                    arguments: None,
+                },
+            ],
+        },
+        nested: [
+            Lit(5),
+        ],
+    }
+    "###);
+
+    assert_eq!(meta, inner.into());
+}
+
+#[test]
+fn test_parse_meta_item_multiple() {
+    let input = "foo(word, name = 5, list(name2 = 6), word2)";
+    let (inner, meta) = (input, input);
+
+    snapshot!(inner as MetaList, @r###"
+    MetaList {
+        path: Path {
+            segments: [
+                PathSegment {
+                    ident: "foo",
+                    arguments: None,
+                },
+            ],
+        },
+        nested: [
+            Meta(Path(Path {
+                segments: [
+                    PathSegment {
+                        ident: "word",
+                        arguments: None,
+                    },
+                ],
+            })),
+            Meta(Meta::NameValue {
+                path: Path {
+                    segments: [
+                        PathSegment {
+                            ident: "name",
+                            arguments: None,
+                        },
+                    ],
+                },
+                lit: 5,
+            }),
+            Meta(Meta::List {
+                path: Path {
+                    segments: [
+                        PathSegment {
+                            ident: "list",
+                            arguments: None,
+                        },
+                    ],
+                },
+                nested: [
+                    Meta(Meta::NameValue {
+                        path: Path {
+                            segments: [
+                                PathSegment {
+                                    ident: "name2",
+                                    arguments: None,
+                                },
+                            ],
+                        },
+                        lit: 6,
+                    }),
+                ],
+            }),
+            Meta(Path(Path {
+                segments: [
+                    PathSegment {
+                        ident: "word2",
+                        arguments: None,
+                    },
+                ],
+            })),
+        ],
+    }
+    "###);
+
+    snapshot!(meta as Meta, @r###"
+    Meta::List {
+        path: Path {
+            segments: [
+                PathSegment {
+                    ident: "foo",
+                    arguments: None,
+                },
+            ],
+        },
+        nested: [
+            Meta(Path(Path {
+                segments: [
+                    PathSegment {
+                        ident: "word",
+                        arguments: None,
+                    },
+                ],
+            })),
+            Meta(Meta::NameValue {
+                path: Path {
+                    segments: [
+                        PathSegment {
+                            ident: "name",
+                            arguments: None,
+                        },
+                    ],
+                },
+                lit: 5,
+            }),
+            Meta(Meta::List {
+                path: Path {
+                    segments: [
+                        PathSegment {
+                            ident: "list",
+                            arguments: None,
+                        },
+                    ],
+                },
+                nested: [
+                    Meta(Meta::NameValue {
+                        path: Path {
+                            segments: [
+                                PathSegment {
+                                    ident: "name2",
+                                    arguments: None,
+                                },
+                            ],
+                        },
+                        lit: 6,
+                    }),
+                ],
+            }),
+            Meta(Path(Path {
+                segments: [
+                    PathSegment {
+                        ident: "word2",
+                        arguments: None,
+                    },
+                ],
+            })),
+        ],
+    }
+    "###);
+
+    assert_eq!(meta, inner.into());
+}
+
+#[test]
+fn test_parse_nested_meta() {
+    let input = "5";
+    snapshot!(input as NestedMeta, @"Lit(5)");
+
+    let input = "list(name2 = 6)";
+    snapshot!(input as NestedMeta, @r###"
+    Meta(Meta::List {
+        path: Path {
+            segments: [
+                PathSegment {
+                    ident: "list",
+                    arguments: None,
+                },
+            ],
+        },
+        nested: [
+            Meta(Meta::NameValue {
+                path: Path {
+                    segments: [
+                        PathSegment {
+                            ident: "name2",
+                            arguments: None,
+                        },
+                    ],
+                },
+                lit: 6,
+            }),
+        ],
+    })
+    "###);
+}
+
+#[test]
+fn test_parse_path() {
+    let input = "::serde::Serialize";
+    snapshot!(input as Meta, @r###"
+    Path(Path {
+        leading_colon: Some,
+        segments: [
+            PathSegment {
+                ident: "serde",
+                arguments: None,
+            },
+            PathSegment {
+                ident: "Serialize",
+                arguments: None,
+            },
+        ],
+    })
+    "###);
+
+    let input = "::serde::Serialize";
+    snapshot!(input as NestedMeta, @r###"
+    Meta(Path(Path {
+        leading_colon: Some,
+        segments: [
+            PathSegment {
+                ident: "serde",
+                arguments: None,
+            },
+            PathSegment {
+                ident: "Serialize",
+                arguments: None,
+            },
+        ],
+    }))
+    "###);
+}