🛡️ Sentinel: [MEDIUM] Fix SQL template injection risk

[sl4m3]

🎯 What
Fixed a medium severity security risk in EpisodicStore.query where .format() was being used to insert where_clause and direction into a SQL query template string.

⚠️ Risk
Using string formatting mechanisms like .format() or f-strings for SQL structure exposes the code to SQL Structural Injection. Even if the variables (like ASC/DESC) are currently heavily sanitized or generated statically internally, using .format() creates a dangerous anti-pattern that can be exploited in the future if input validation logic is modified or bypassed.

🛡️ Solution
Refactored the SQL query building to use explicit static string concatenation along with strict if/else logic specifically for identifiers like the ASC/DESC direction parameter. This makes the query completely immune to structural manipulation from dynamic data and complies with the LedgerMind secure coding standards for SQL template generation.

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PR created automatically by Jules for task 8024720498327344283 started by @sl4m3

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