feat: pivot to AI-native task management platform (#232)

Replace the agent framework codebase with a new monorepo structure
for an AI-native Linear-like product where agents are first-class citizens.

New architecture:
- server/ — Go backend (Chi + gorilla/websocket + sqlc)
  - API server with REST routes for issues, agents, inbox, workspaces
  - WebSocket hub for real-time updates
  - Local daemon entry point for agent runtime connection
  - PostgreSQL migration with 13 tables (issue, agent, inbox, etc.)
  - WebSocket protocol types for server<->daemon communication
- apps/web/ — Next.js 16 frontend
  - Dashboard layout with sidebar navigation
  - Route skeleton: inbox, issues, agents, board, settings
- packages/ui/ — Preserved shadcn/ui design system (26+ components)
- packages/types/ — Full API contract types (Issue, Agent, Workspace, Inbox, Events)
- packages/sdk/ — REST ApiClient + WebSocket WSClient
- packages/store/ — Zustand stores (issue, agent, inbox, auth)
- packages/hooks/ — React hooks (useIssues, useAgents, useInbox, useRealtime)
- packages/utils/ — Shared utilities

Removed: apps/cli, apps/desktop, apps/mobile, apps/gateway,
packages/core, skills/, and all agent-framework code.

Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

server/pkg/db/queries/issue.sql

@@ -0,0 +1,35 @@
+-- name: ListIssues :many
+SELECT * FROM issue
+WHERE workspace_id = $1
+ORDER BY position ASC, created_at DESC
+LIMIT $2 OFFSET $3;
+
+-- name: GetIssue :one
+SELECT * FROM issue
+WHERE id = $1;
+
+-- name: CreateIssue :one
+INSERT INTO issue (
+    workspace_id, title, description, status, priority,
+    assignee_type, assignee_id, creator_type, creator_id,
+    parent_issue_id, acceptance_criteria, context_refs,
+    repository, position
+) VALUES (
+    $1, $2, $3, $4, $5, $6, $7, $8, $9, $10, $11, $12, $13, $14
+) RETURNING *;
+
+-- name: UpdateIssue :one
+UPDATE issue SET
+    title = COALESCE($2, title),
+    description = COALESCE($3, description),
+    status = COALESCE($4, status),
+    priority = COALESCE($5, priority),
+    assignee_type = $6,
+    assignee_id = $7,
+    position = COALESCE($8, position),
+    updated_at = now()
+WHERE id = $1
+RETURNING *;
+
+-- name: DeleteIssue :exec
+DELETE FROM issue WHERE id = $1;