Add port mappings feature, update app icon, and enhance default instructions

- Add per-project port mapping configuration (host:container port pairs with
  TCP/UDP protocol) stored in project config and applied as Docker port
  bindings at container creation. Port changes trigger automatic container
  recreation via fingerprint detection.
- Create PortMappingsModal UI component following the same pattern as
  EnvVarsModal, integrated into ProjectCard config panel.
- Inject port mapping details into CLAUDE_INSTRUCTIONS so Claude inside the
  container knows which ports are available for testing services.
- Update default global instructions for new installs to encourage use of
  subagents for long-running and parallel tasks.
- Replace app icons with new v2 sun logo design for better visibility at
  small sizes (taskbar/dock).

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

app/src/lib/types.ts

@@ -8,6 +8,12 @@ export interface ProjectPath {
   mount_name: string;
 }
 
+export interface PortMapping {
+  host_port: number;
+  container_port: number;
+  protocol: string;
+}
+
 export interface Project {
   id: string;
   name: string;
@@ -22,6 +28,7 @@ export interface Project {
   git_user_name: string | null;
   git_user_email: string | null;
   custom_env_vars: EnvVar[];
+  port_mappings: PortMapping[];
   claude_instructions: string | null;
   created_at: string;
   updated_at: string;