Add Character Roster Editor and PIC/WPORT Pixel Editor apps with tests

[martydill]

Motivation

• Add standalone WinForms tools to edit Wizardry 6 character rosters (PCFILE.DBS) and pixel art (WPORT*.EGA / *.PIC) to improve editing workflows.
• Ensure edits preserve unknown bytes and avoid accidental file corruption by adding deterministic parsing/serialization and isolation tests.

Description

• Introduces a new CharacterRosterEditor WinForms app with CharacterRecord, PcfileDocument, MainForm, Program, solution and project files, and AssemblyInfo exposing internals to tests.
• Adds CharacterRecord parsing/serialization that preserves raw record bytes and only writes known mapped fields back, plus lookup helpers for race/gender/class and portrait preview logic that resolves WPORT frames.
• Introduces a new PicEditor WinForms app with ImageFormats (WPORT/PIC decoding and WPORT encoding), FrameEditingService, UI (MainForm), project and solution files, and AssemblyInfo.
• Adds unit test projects and tests: CharacterRosterEditor.Tests/CharacterRecordIsolationTests which verifies field isolation and round-trips at record and file level, and PicEditor.Tests/FrameEditingTests which verifies frame copy/paste, duplication, insertion, deletion and WPORT save/reload behavior.
• Adds documentation files docs/CHARACTER_ROSTER_EDITOR.md and docs/PIC_EDITOR.md describing features, file coverage and build/run instructions.

Testing

• Ran CharacterRosterEditor.Tests::CharacterRecordIsolationTests (NUnit) which exercises per-field mutation, ToBytes/FromBytes round-trips and file-level isolation; the tests completed successfully.
• Ran PicEditor.Tests::FrameEditingTests (NUnit) which covers FrameEditingService operations and ImageFormats WPORT save/load behavior; the tests completed successfully.

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Codex Task