Restructure src/ modules with consistent internal organization

Reorganize major src/ directories to follow a consistent pattern with
core/, menu/, submenu/, inputs/, logs/, layout/, feedback/ subdirectories.

Changes by module:

- stores/: Move 5 store files to stores/core/
- utils/: Create core/ (terminal, tools, etc.) and menu/ (progress-bar)
- api/: Create copilot/core/, copilot/auth/, ollama/core/
- providers/: Create core/, copilot/core/, copilot/auth/, ollama/core/, login/core/
- ui/: Create core/, banner/core/, banner/menu/, spinner/core/,
       input-editor/core/, components/core/, components/menu/
- tools/: Create core/ for registry.ts and types.ts
- tui-solid/: Reorganize components/ into menu/, submenu/, inputs/,
              logs/, modals/, panels/, layout/, feedback/
- commands/: Create core/ for runner.ts and handlers.ts
- services/: Create core/ for agent.ts, permissions.ts, session.ts,
             executor.ts, config.ts

All imports updated to use new paths. TypeScript compilation verified.

src/constants/multi-agent.ts

@@ -0,0 +1,112 @@
+/**
+ * Multi-Agent Constants
+ *
+ * Configuration defaults, messages, and descriptions for multi-agent execution.
+ */
+
+import type { AgentExecutionMode, ConflictStrategy } from "@/types/multi-agent";
+
+/**
+ * Default configuration values
+ */
+export const MULTI_AGENT_DEFAULTS = {
+  maxConcurrent: 3,
+  timeout: 300000, // 5 minutes
+  executionMode: "adaptive" as AgentExecutionMode,
+  conflictStrategy: "serialize" as ConflictStrategy,
+  abortOnFirstError: false,
+  conflictCheckInterval: 1000, // 1 second
+  maxRetries: 2,
+} as const;
+
+/**
+ * Resource limits
+ */
+export const MULTI_AGENT_LIMITS = {
+  maxAgentsPerRequest: 10,
+  maxConcurrentRequests: 3,
+  maxQueuedAgents: 20,
+  maxConflictsBeforeAbort: 5,
+} as const;
+
+/**
+ * Execution mode descriptions
+ */
+export const EXECUTION_MODE_DESCRIPTIONS: Record<AgentExecutionMode, string> = {
+  sequential: "Execute agents one after another, safest for file modifications",
+  parallel: "Execute all agents concurrently, fastest but may cause conflicts",
+  adaptive: "Start parallel, automatically serialize when conflicts detected",
+} as const;
+
+/**
+ * Conflict strategy descriptions
+ */
+export const CONFLICT_STRATEGY_DESCRIPTIONS: Record<ConflictStrategy, string> = {
+  serialize: "Wait for conflicting agent to complete before proceeding",
+  "abort-newer": "Abort the agent that started later when conflict detected",
+  "merge-results": "Attempt to merge changes from both agents",
+  isolated: "Each agent works in isolated context, merge at end",
+} as const;
+
+/**
+ * Error messages
+ */
+export const MULTI_AGENT_ERRORS = {
+  MAX_AGENTS_EXCEEDED: (max: number) =>
+    `Cannot spawn more than ${max} agents in a single request`,
+  MAX_CONCURRENT_EXCEEDED: (max: number) =>
+    `Maximum concurrent agents (${max}) reached`,
+  AGENT_NOT_FOUND: (name: string) =>
+    `Agent "${name}" not found in registry`,
+  AGENT_ALREADY_RUNNING: (id: string) =>
+    `Agent "${id}" is already running`,
+  EXECUTION_TIMEOUT: (agentId: string, timeout: number) =>
+    `Agent "${agentId}" timed out after ${timeout}ms`,
+  CONFLICT_RESOLUTION_FAILED: (filePath: string) =>
+    `Failed to resolve conflict for file: ${filePath}`,
+  EXECUTION_ABORTED: "Execution aborted by user",
+  INVALID_EXECUTION_MODE: (mode: string) =>
+    `Invalid execution mode: ${mode}`,
+  INVALID_CONFLICT_STRATEGY: (strategy: string) =>
+    `Invalid conflict strategy: ${strategy}`,
+  TOO_MANY_CONFLICTS: (count: number) =>
+    `Too many conflicts detected (${count}), aborting execution`,
+} as const;
+
+/**
+ * Status messages
+ */
+export const MULTI_AGENT_MESSAGES = {
+  STARTING: "Starting multi-agent execution",
+  AGENT_SPAWNED: (name: string) => `Spawned agent: ${name}`,
+  AGENT_COMPLETED: (name: string) => `Agent completed: ${name}`,
+  AGENT_FAILED: (name: string, error: string) =>
+    `Agent failed: ${name} - ${error}`,
+  CONFLICT_DETECTED: (file: string, agents: string[]) =>
+    `Conflict detected on ${file} between agents: ${agents.join(", ")}`,
+  CONFLICT_RESOLVED: (file: string, strategy: string) =>
+    `Conflict resolved for ${file} using ${strategy}`,
+  EXECUTION_COMPLETE: (success: number, failed: number) =>
+    `Execution complete: ${success} succeeded, ${failed} failed`,
+  WAITING_FOR_CONFLICT: (agentId: string) =>
+    `Agent ${agentId} waiting for conflict resolution`,
+} as const;
+
+/**
+ * Agent ID generation prefix
+ */
+export const AGENT_ID_PREFIX = "agent_";
+
+/**
+ * Request ID generation prefix
+ */
+export const REQUEST_ID_PREFIX = "req_";
+
+/**
+ * File lock constants
+ */
+export const FILE_LOCK = {
+  acquireTimeout: 5000, // 5 seconds
+  retryInterval: 100, // 100ms
+  maxRetries: 50,
+} as const;