Add vertical swing support to Mitsubishi Heavy code 1686

[qq-123456a]

Summary

• add seven vertical airflow settings to Mitsubishi Heavy device code 1686: off, swing, highest, high, middle, low, and lowest
• regenerate the complete Broadlink command matrix for SRK20/25/35/50ZSA-W models from the verified Mitsubishi Heavy 152-bit protocol
• document vertical swing support in the climate code table

Validation

• hardware-tested through Home Assistant with a Broadlink controller
• validated all 2,275 generated on-state commands plus the off command for Broadlink packet structure, MHI signature, and complementary bytes
• confirmed mode, temperature, and fan bytes match all 324 valid existing learned commands
• regenerated one malformed learned command present in the existing matrix

No SmartIR core changes are required. Horizontal swing, 3D Auto, presets, and self-clean are intentionally outside this PR because the current SmartIR climate schema exposes one swing dimension.