chore(meta): point agents at sprint briefings in CLAUDE.md

Sprint briefings (docs/sprints/sprint-N/{team}.md) are now the primary
starting point for implementation work. Per-agent briefings remain as
background context.

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

CLAUDE.md

@@ -19,6 +19,7 @@ docs/
   briefings/          # Per-agent context briefings (maintained by Qatux)
   architecture/       # Technical architecture documents
   design/             # Game design documents
+  sprints/            # Sprint briefings per team (server.md, client.md, joint.md, content.md)
   workshops/          # Workshop briefs and outputs (per-workshop subdirectories)
 db/
   commonwealth.db     # SQLite ticketing database
@@ -51,9 +52,10 @@ See [docs/DEVOPS.md](docs/DEVOPS.md) for build, test, lint, and CI procedures. A
 ## Agent Instructions
 
 ### Before starting work
-1. Read your briefing at `docs/briefings/{your-name}.md` for current project context
-2. Read the relevant `decisions/*.md` domain file(s) listed in your briefing
-3. Check `docs/discussions/` for recent discussion rounds if needed
+1. Read your sprint briefing at `docs/sprints/sprint-N/{team}.md` for current tasks
+2. Use `db/connectors/ticket show <id>` for full ticket details
+3. Read the relevant `decisions/*.md` domain file(s) referenced in the briefing
+4. Background context: `docs/briefings/{your-name}.md`, `docs/discussions/`
 
 ### SQLite access
 **Never use the `sqlite3` CLI** - it crashes in Claude Code due to a known std::bad_alloc bug.