Fixed _resolve_hot_max_tokens() to read hot_max_tokens from the correct
sub-key in context_policy_json. The value is stored under
context_policy_json["acms_config"]["hot_max_tokens"] by
'agents project context set --hot-max-tokens', not at the top level.
The previous read (config_dict.get("hot_max_tokens")) always returned
None, causing the assembler to silently use the global 16K default even
when a project-level override was configured.
Also adds two Behave regression scenarios with @tdd_issue @tdd_issue_11035
tags that exercise the real DB query code path via a mocked
NamespacedProjectModel row, verifying:
1. hot_max_tokens=32000 in acms_config is applied to CoreContextBudget
and ContextRequest (override path).
2. Missing hot_max_tokens falls back to the constructor-injected global
default of 4096 (fallback path).
Module-level import json added to steps file; redundant inline MagicMock
import removed.
ISSUES CLOSED: #11035
ISSUES CLOSED: #11215
hamza.khyari