Initial Modular Refactor & Core Analysis Features

This release represents a significant refactor of the Firebird analysis tool, introducing a more robust and modular architecture for safer and deeper database inspection.

Key Changes:

• Modular Architecture: Core logic has been split into dedicated units (uPageAnalyzer, uDatabaseStats, uFlagManager, uBtreePage, uRecordParser) for better maintainability and separation of concerns.
• Corrected Data Structures: Fixed critical errors in TPag and THdr definitions in uStructs to align with Firebird's internal format (fbint-page-1.html).
• Improved Data Page Analysis: uDataPage now correctly parses TData_Page_Fixed_Part and TDpg_rpt, including accurate calculation of the data area start and validation of record fragment offsets.
• New Analysis Modules:
  • uPageAnalyzer: Centralizes page reading and type identification.
  • uDatabaseStats: Calculates and reports detailed statistics on page types, transaction states (via TIP), and relations.
  • uFlagManager: Provides safe reading and writing of database header flags.
  • uBtreePage: Adds capability to analyze B-Tree index pages.
  • uRecordParser: (New) Parses headers of individual record fragments, a foundational step towards MVCC analysis.
• Refactored Main UI (main.pas): Now leverages the new modules for analysis, data extraction, and flag management. Improved error handling and UI updates. Removed dependency on incorrect structures from uCommon.
• Enhanced uDatabase.pas: Updated to use corrected types and safer page I/O methods.
• Updated Documentation: Improved README.md with clearer features, goals, and technical details. Added a basic user manual (manual.md).
• Deprecated/Removed: Outdated modules like uHeaderPage, uPoiner, uGenPage are no longer used.

This lays the groundwork for more advanced recovery features, especially MVCC-aware data reconstruction.