fix: distinguish pending broker orders from executions

[Pigbibi]

Summary

• Classifies IBKR non-terminal order states as pending reconciliation rather than execution success.
• Retains broker order IDs in telemetry and reconciliation records.
• Renders pending buy and sell confirmations distinctly in notifications.
• Preserves execution deduplication while a broker order awaits a final state.
• Blocks new buys and top-ups when the strategy explicitly flags the account below its recommended minimum; strategy-driven reductions remain allowed.

Validation

• Execution, rebalance and notification tests: 70 passed.
• Request-handling and runtime-broker-adapter tests: 55 passed; 3 existing warnings.
• Ruff check passed for all changed files.