feat(db): add team column to ticket system

Adds a comma-separated team field to tickets so work can be
attributed to server, client, or joint teams. Includes --team
filter on list, --team on create, and a new team subcommand.
Schema, CLI, and skill docs all updated.

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

db/schema.sql

@@ -14,6 +14,7 @@ CREATE TABLE IF NOT EXISTS tickets (
     status TEXT NOT NULL DEFAULT 'backlog' CHECK(status IN ('backlog', 'ready', 'in_progress', 'review', 'done', 'cancelled')),
     priority TEXT DEFAULT 'medium' CHECK(priority IN ('critical', 'high', 'medium', 'low')),
     assigned_to TEXT,
+    team TEXT,          -- comma-separated team names, e.g. 'server', 'client,server'
     decision_ref TEXT,  -- e.g. 'D-010' or 'Q-001'
     sprint_id INTEGER REFERENCES sprints(id),
     created_at TEXT NOT NULL DEFAULT (datetime('now')),
@@ -58,6 +59,7 @@ CREATE INDEX IF NOT EXISTS idx_tickets_parent ON tickets(parent_id);
 CREATE INDEX IF NOT EXISTS idx_tickets_sprint ON tickets(sprint_id);
 CREATE INDEX IF NOT EXISTS idx_tickets_assigned ON tickets(assigned_to);
 CREATE INDEX IF NOT EXISTS idx_tickets_decision ON tickets(decision_ref);
+CREATE INDEX IF NOT EXISTS idx_tickets_team ON tickets(team);
 CREATE INDEX IF NOT EXISTS idx_history_ticket ON ticket_history(ticket_id);
 
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