docs(discussions): add Rounds 15-16, retire DISCUSSION.md

Round 15: README.md Steam page placeholder (Miri + Mellanie)
- Created README.md with game description for Steam page
- Placeholder structure with lorem ipsum for undetermined content

Round 16: Faction development (Miri, Paula, Gestalt)
- Full development of six factions with lore, politics, mechanics
- 3D reputation system (Trust × Usefulness × Exposure)
- Mechanical grounding with "First 30 Minutes" test
- v0.1 recommendation: Commission + Severance
- Session flagged for team input

Process changes (D-022):
- Retired DISCUSSION.md, work directly in round files
- Qatux mandatory in all team interactions
- Updated CLAUDE.md and agent personas

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

docs/discussions/README.md

@@ -16,4 +16,7 @@ Historical discussion rounds from the Commonwealth game design process.
 | 10 | Map, Fog & Borderless | D-011, D-012, D-013, D-014 | [round-10](round-10-map-fog-borderless.md) |
 | 11 | Insert, Sound & Camera | D-015, D-016, D-017, D-018 | [round-11](round-11-insert-sound-camera.md) |
 | 12 | Top-Down Final | D-019 | [round-12](round-12-top-down-final.md) |
-| 13 | Engine Selection | D-020, R-004–R-010 | Active in DISCUSSION.md |
+| 13 | Engine Selection | D-020, R-004–R-010 | [round-13](round-13-engine-selection.md) |
+| 14 | Setting Foundation — The Settled Reach | D-021 | [round-14](round-14-worldbuilding-settled-reach.md) |
+| 15 | README / Steam Page Placeholder | - | [round-15](round-15-readme-steam-page.md) |
+| 16 | Factions — Building a Fuller Narrative Picture | AWAITING INPUT | [complete](round-16-factions-complete.md), [lore](round-16-factions.md), [mechanics](round-16-faction-mechanics.md), [notes](round-16-session-notes.md) |