feat: add Omega Mac native macOS SwiftUI chat app

Native macOS counterpart to the web Omega agent, connecting directly
to the OpenAI API and TPMJS tool registry (1M+ AI-ready tools).

- SwiftUI app targeting macOS 15+ with dark theme
- Full agentic loop: auto-discover tools via BM25, stream OpenAI
  responses, execute tools via remote sandbox, loop up to 10x
- SwiftData persistence for conversations, messages, tool runs
- Keychain storage for API keys and environment variables
- SSE streaming via URLSession.bytes with custom parser
- Actor-based services (OpenAIService, TPMJSRegistryService)
- NavigationSplitView layout with sidebar + chat detail
- MarkdownUI for rendering assistant responses
- Settings: API key, model picker, env vars, custom system prompt
- Keyboard shortcuts: Cmd+N new chat, Cmd+, settings, Enter send

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

apps/omega-mac/OmegaMac/Models/Conversation.swift

@@ -0,0 +1,41 @@
+import Foundation
+import SwiftData
+
+@Model
+final class Conversation {
+    var id: UUID
+    var title: String?
+    var createdAt: Date
+    var updatedAt: Date
+    var executionState: String // "idle" | "running"
+    var inputTokensTotal: Int
+    var outputTokensTotal: Int
+
+    @Relationship(deleteRule: .cascade, inverse: \Message.conversation)
+    var messages: [Message]
+
+    @Relationship(deleteRule: .cascade, inverse: \ToolCallRecord.conversation)
+    var toolRuns: [ToolCallRecord]
+
+    init(
+        title: String? = nil
+    ) {
+        self.id = UUID()
+        self.title = title
+        self.createdAt = Date()
+        self.updatedAt = Date()
+        self.executionState = "idle"
+        self.inputTokensTotal = 0
+        self.outputTokensTotal = 0
+        self.messages = []
+        self.toolRuns = []
+    }
+
+    var displayTitle: String {
+        title ?? "New Conversation"
+    }
+
+    var sortedMessages: [Message] {
+        messages.sorted { $0.createdAt < $1.createdAt }
+    }
+}

apps/omega-mac/OmegaMac/Models/EnvVar.swift

@@ -0,0 +1,18 @@
+import Foundation
+import SwiftData
+
+@Model
+final class EnvVar {
+    var id: UUID
+    var keyName: String
+    /// Last 4 characters of the value (for display hint)
+    var valueHint: String
+    var createdAt: Date
+
+    init(keyName: String, valueHint: String) {
+        self.id = UUID()
+        self.keyName = keyName
+        self.valueHint = valueHint
+        self.createdAt = Date()
+    }
+}

apps/omega-mac/OmegaMac/Models/Message.swift

@@ -0,0 +1,141 @@
+import Foundation
+import SwiftData
+
+enum MessageRole: String, Codable {
+    case user = "USER"
+    case assistant = "ASSISTANT"
+    case tool = "TOOL"
+    case system = "SYSTEM"
+}
+
+@Model
+final class Message {
+    var id: UUID
+    var role: MessageRole
+    var content: String
+    var createdAt: Date
+    var inputTokens: Int?
+    var outputTokens: Int?
+
+    /// JSON-encoded array of tool calls (for assistant messages)
+    var toolCallsJSON: Data?
+
+    var conversation: Conversation?
+
+    init(
+        role: MessageRole,
+        content: String,
+        conversation: Conversation? = nil,
+        inputTokens: Int? = nil,
+        outputTokens: Int? = nil,
+        toolCalls: [ToolCallData]? = nil
+    ) {
+        self.id = UUID()
+        self.role = role
+        self.content = content
+        self.createdAt = Date()
+        self.inputTokens = inputTokens
+        self.outputTokens = outputTokens
+        self.conversation = conversation
+        if let toolCalls {
+            self.toolCallsJSON = try? JSONEncoder().encode(toolCalls)
+        }
+    }
+
+    var toolCalls: [ToolCallData] {
+        get {
+            guard let data = toolCallsJSON else { return [] }
+            return (try? JSONDecoder().decode([ToolCallData].self, from: data)) ?? []
+        }
+        set {
+            toolCallsJSON = try? JSONEncoder().encode(newValue)
+        }
+    }
+}
+
+/// Serializable tool call data stored in messages
+struct ToolCallData: Codable, Identifiable {
+    var id: String { toolCallId }
+    let toolCallId: String
+    let toolName: String
+    let args: JSONValue?
+    let output: JSONValue?
+
+    init(toolCallId: String, toolName: String, args: JSONValue? = nil, output: JSONValue? = nil) {
+        self.toolCallId = toolCallId
+        self.toolName = toolName
+        self.args = args
+        self.output = output
+    }
+}
+
+/// A type-erased JSON value for encoding/decoding arbitrary JSON
+enum JSONValue: Codable, Equatable, Sendable {
+    case string(String)
+    case number(Double)
+    case bool(Bool)
+    case object([String: JSONValue])
+    case array([JSONValue])
+    case null
+
+    init(from decoder: Decoder) throws {
+        let container = try decoder.singleValueContainer()
+        if container.decodeNil() {
+            self = .null
+        } else if let b = try? container.decode(Bool.self) {
+            self = .bool(b)
+        } else if let n = try? container.decode(Double.self) {
+            self = .number(n)
+        } else if let s = try? container.decode(String.self) {
+            self = .string(s)
+        } else if let arr = try? container.decode([JSONValue].self) {
+            self = .array(arr)
+        } else if let obj = try? container.decode([String: JSONValue].self) {
+            self = .object(obj)
+        } else {
+            self = .null
+        }
+    }
+
+    func encode(to encoder: Encoder) throws {
+        var container = encoder.singleValueContainer()
+        switch self {
+        case .string(let s): try container.encode(s)
+        case .number(let n): try container.encode(n)
+        case .bool(let b): try container.encode(b)
+        case .object(let o): try container.encode(o)
+        case .array(let a): try container.encode(a)
+        case .null: try container.encodeNil()
+        }
+    }
+
+    /// Convert any Codable/Sendable value to JSONValue
+    static func from(_ value: Any) -> JSONValue {
+        if let s = value as? String { return .string(s) }
+        if let n = value as? NSNumber {
+            if CFBooleanGetTypeID() == CFGetTypeID(n) {
+                return .bool(n.boolValue)
+            }
+            return .number(n.doubleValue)
+        }
+        if let b = value as? Bool { return .bool(b) }
+        if let i = value as? Int { return .number(Double(i)) }
+        if let d = value as? Double { return .number(d) }
+        if let arr = value as? [Any] { return .array(arr.map { from($0) }) }
+        if let obj = value as? [String: Any] {
+            return .object(obj.mapValues { from($0) })
+        }
+        return .null
+    }
+
+    /// Pretty-print JSON
+    var prettyString: String {
+        let encoder = JSONEncoder()
+        encoder.outputFormatting = [.prettyPrinted, .sortedKeys]
+        guard let data = try? encoder.encode(self),
+              let str = String(data: data, encoding: .utf8) else {
+            return "null"
+        }
+        return str
+    }
+}

apps/omega-mac/OmegaMac/Models/ToolCallRecord.swift

@@ -0,0 +1,51 @@
+import Foundation
+import SwiftData
+
+@Model
+final class ToolCallRecord {
+    var id: UUID
+    var toolName: String
+    var toolCallId: String
+    var status: String // "running" | "success" | "error"
+    var inputJSON: Data?
+    var outputJSON: Data?
+    var errorMessage: String?
+    var executionTimeMs: Int?
+    var createdAt: Date
+    var completedAt: Date?
+
+    var conversation: Conversation?
+
+    init(
+        toolName: String,
+        toolCallId: String,
+        conversation: Conversation? = nil
+    ) {
+        self.id = UUID()
+        self.toolName = toolName
+        self.toolCallId = toolCallId
+        self.status = "running"
+        self.createdAt = Date()
+        self.conversation = conversation
+    }
+
+    var input: JSONValue? {
+        get {
+            guard let data = inputJSON else { return nil }
+            return try? JSONDecoder().decode(JSONValue.self, from: data)
+        }
+        set {
+            inputJSON = try? JSONEncoder().encode(newValue)
+        }
+    }
+
+    var output: JSONValue? {
+        get {
+            guard let data = outputJSON else { return nil }
+            return try? JSONDecoder().decode(JSONValue.self, from: data)
+        }
+        set {
+            outputJSON = try? JSONEncoder().encode(newValue)
+        }
+    }
+}

apps/omega-mac/OmegaMac/Models/UserSettings.swift

@@ -0,0 +1,17 @@
+import Foundation
+import SwiftData
+
+@Model
+final class UserSettings {
+    var id: UUID
+    var systemPrompt: String?
+    var selectedModel: String
+    var pinnedToolIds: [String]
+
+    init() {
+        self.id = UUID()
+        self.systemPrompt = nil
+        self.selectedModel = "gpt-4.1-mini"
+        self.pinnedToolIds = []
+    }
+}