feat: Add Southlands Player's Guide (Kobold Press) - OGL Compliant

[Mnehmos]

Summary

This PR adds content from the Southlands Player's Guide by Kobold Press to the Open5e API, with strict adherence to the Open Game License (OGL) terms.

Content Added

Species (6 base + 10 subspecies)

• Catfolk (Basteti, Nkosi)
• Gnoll (Civilized, Savage, Desert, Necropolis)
• Jinnborn (Speaker, Shaper)
• Minotaur
• Tosculi
• Heru (Ravenfolk)
• Lizardfolk (Murkscale, Velesborn)
• Ramag
• Subek
• Trollkin (Southern)

Subclasses

• Barbarian: Path of the Inner Eye, Path of the Souleater
• Bard: College of the Cat, College of the Sky
• Cleric: Desert Domain, Serpent Domain
• Fighter: Ankole Knight, Farseer
• Paladin: Oath of the Giving Grave, Oath of the Keeper
• Ranger: Wasteland Strider
• Rogue: Tomb Raider
• Warlock: School of Desiderates
• Wizard: Oath of the Plaguetouched

Backgrounds (4)

• Desert Runner
• Freebooter
• Scoundrel
• Servant of the Jinn

Items, Weapons, and Spells

• Camel Saddle (Item)
• Flyssa, Khopesh (Weapons)
• Various spells from the appendix

OGL Compliance

This submission was subjected to a rigorous 6-pass audit to ensure all content is designated as Open Game Content per the source material's copyright page:

1. Pass 1 - OGC List Compliance: Every entry was verified against the explicit OGC declaration. Items NOT listed (Path of the Ankole, The Great Serpent, Siwali Embalmer) were removed.
2. Pass 2 - PI Keyword Scan: All files were searched for Product Identity terms (Midgard, Bastet, Horus, Southlands, etc.).
3. Pass 3 - Narrative Scrub: Descriptions were edited to remove setting-specific lore and proper noun references.
4. Pass 4 - Language Trait Removal: All racial 'Languages' traits were deleted, as the OGC declaration explicitly excludes languages.
5. Pass 5 - Cross-Reference: Verified ambiguous entries against the OGC list.
6. Pass 6 - Final Verification: Automated grep scans confirm 0 remaining PI terms.

Important Notes

• No PDF Included: This branch was created fresh from upstream/main to ensure no copyrighted material (PDFs, raw sources) exists in the commit history.
• Sanitized Descriptions: All flavor text references to Midgard setting locations and deities have been genericized (e.g., 'Bastet' → 'the cat goddess').

Testing

• All JSON files have been validated for syntax.
• No dangling parent references exist for deleted subclasses/backgrounds.