fix(history): skip update entity restoration

[mgazza]

Summary

• skip HA history restoration for update entities, which are synthesised after release discovery and are non-restorable
• prevent an absent update state from registering an empty long-range HAHistory lookup that is retried periodically
• retain the existing history fallback for ordinary entities

Problem

Update entities are generated at runtime and explicitly non-restorable. When an update entity has no current state during startup, attempting to restore it from entity history adds an empty lookup to HAHistory tracking. The tracker then retries that unnecessary lookup, producing avoidable backend load and timeout noise.

Tests

• config_item_range_clamp
• plugin_startup
• hahistory
• pre-commit: whitespace, EOF, Ruff, Black, cspell

Risk

load_user_config is a central startup path, but the behaviour change is restricted to type == "update". Regression coverage verifies normal history fallback remains active.