Add TCP transport E2E tests for device-profiler

[groupsky]

Description

Add E2E test coverage for device-profiler TCP transport mode.

Context

PR #366 adds comprehensive E2E tests for device-profiler but only covers serial RTU transport. The device-profiler supports TCP transport via --port host:port format, but this is currently untested in E2E.

Test Scenarios

TCP Connection

• Start TCP-based emulator (or use netcat/socat TCP bridge)
• Run profiler with TCP address format

ya-modbus-profile --port localhost:5020 --slave-id 1 --type holding --start 0 --end 10

• Verify successful register scanning over TCP

TCP Port Validation

• Test valid port numbers (1-65535)
• Test invalid port numbers (0, 65536, negative)
• Test invalid format (missing colon, missing port, etc.)

TCP-Specific Errors

• Connection refused (no server listening)
• Connection timeout
• Host not found

Implementation

Add tests to tests/e2e/tests/05-device-profiler.bats:

• Use existing helpers where possible
• May need to create TCP emulator helper or use existing TCP emulator fixtures
• Follow patterns from PR test(e2e): add device-profiler register scanning tests #366

Acceptance Criteria

• TCP connection test passes
• TCP port validation tests pass
• TCP error scenarios handled gracefully
• Tests use existing fixtures/helpers
• Tests clean up resources in teardown

Related

• PR test(e2e): add device-profiler register scanning tests #366 (device-profiler E2E tests)
• Issue Add device-profiler E2E tests #239 (original E2E test request)