docs: Add Gemini round 3 — provision.json validated, architecture locked

docs/consultations/gemini-modpack-installer-followup-2026-04-15.md

@@ -148,3 +148,51 @@ Redis is a new infrastructure dependency for LuckPerms messaging service.
 2. Holly review with feature descriptions
 3. Holly names her bot
 4. Final spec → Code
+
+---
+
+## Gemini's Response — Round 3: provision.json Validation (April 15, 2026)
+
+**Summary:** Payload validated with 5 bulletproofing additions.
+
+### Validated provision.json
+
+```json
+{
+  "version": "1.0",
+  "schematic_name": "firefrost-spawn-v1.schem",
+  "schematic_url": "https://downloads.firefrostgaming.com/...",
+  "schematic_hash": "e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855",
+  "spawn_type": "standard",
+  "spawn_coords": { "x": -5000, "y": 64, "z": -5000 },
+  "paste_origin": "center",
+  "worldspawn_offset": { "x": 0, "y": 0, "z": 0 },
+  "command_blocks": [
+    { "position": { "x": -4998, "y": 65, "z": -4998 }, "facing": "up" },
+    { "position": { "x": -5002, "y": 65, "z": -4998 }, "facing": "up" },
+    { "position": { "x": -4998, "y": 65, "z": -5002 }, "facing": "up" },
+    { "position": { "x": -5002, "y": 65, "z": -5002 }, "facing": "up" }
+  ],
+  "self_destruct_on_success": true
+}
+```
+
+### Why the Additions
+- `schematic_hash` — SHA-256 checksum verification before paste. Catches partial downloads.
+- `paste_origin` — center vs corner declaration so building lands exactly on target coords every time.
+- `facing` on command blocks — Minecraft block states matter. `facing=up` ensures buttons don't pop off.
+- `self_destruct_on_success` — explicit termination orders once paste + worldspawn set confirmed.
+- `version` — future-proof the payload format.
+
+### Gemini's Question
+> "Are we officially locking in this architecture to start the Code phase, or should we map out the PostgreSQL schema updates for `server_config` and the `pg-boss` queue first?"
+
+**Answer:** Map out the PostgreSQL schema and pg-boss queue first. We want Code to have a complete spec before touching a line of code. No half-baked dispatches.
+
+---
+
+## ARCHITECTURE LOCKED ✅
+
+Full consultation complete. Three rounds, all questions answered, provision.json validated.
+
+**Ready for:** Holly review → final spec → Code