docs(docs): add frontmatter to all sprint briefings

Standardized YAML frontmatter on all 115 sprint briefing files across
sprints 1-26 with title, description, type, status, sprint number, and
team fields.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

docs/sprints/sprint-8/audio.md

@@ -1,3 +1,12 @@
+---
+title: "Sprint 8 — Audio Briefing"
+description: "Interaction audio assets carry-over — remaining 2 of 6 assets"
+type: sprint
+status: archived
+sprint: 8
+team: "audio"
+---
+
 # Sprint 8: React — Audio Tasks
 
 **Goal:** Activate the dialogue pipeline end-to-end — player talks to NPCs, NPCs respond, the world reacts.

docs/sprints/sprint-8/client.md

@@ -1,3 +1,12 @@
+---
+title: "Sprint 8 — Client Briefing"
+description: "Dialogue response selection, walk-away mechanic, confrontation text styling"
+type: sprint
+status: archived
+sprint: 8
+team: "client"
+---
+
 # Sprint 8: React — Client Tasks
 
 **Goal:** Activate the dialogue pipeline end-to-end — player talks to NPCs, NPCs respond, the world reacts.

docs/sprints/sprint-8/joint.md

@@ -1,3 +1,12 @@
+---
+title: "Sprint 8 — Joint Briefing"
+description: "End-to-end dialogue pipeline activation, NPC conversations, world reactions"
+type: sprint
+status: archived
+sprint: 8
+team: "joint"
+---
+
 # Sprint 8: React — Joint / Integration Tasks
 
 **Goal:** Activate the dialogue pipeline end-to-end — player talks to NPCs, NPCs respond, the world reacts.

docs/sprints/sprint-8/server.md

@@ -1,3 +1,12 @@
+---
+title: "Sprint 8 — Server Briefing"
+description: "Dialogue selection pipeline, walk-away KG recording, anomaly detection, monologue timing"
+type: sprint
+status: archived
+sprint: 8
+team: "server"
+---
+
 # Sprint 8: React — Server Tasks
 
 **Goal:** Activate the dialogue pipeline end-to-end — player talks to NPCs, NPCs respond, the world reacts.