step 4: fresh kernel-only migrations

Deleted all 23+23 old chat-switchboard migration files.
Wrote 9+9 clean kernel-only migrations in postgres/ and sqlite/ subdirs.

27 tables per dialect covering all 20 store interfaces:
  001: users, refresh_tokens, policies, settings, presence, oidc
  002: teams, team_members, groups, group_members
  003: packages, package_user_settings, ext_permissions, ext_data_tables
  004: ext_connections, ext_dependencies, resource_grants
  005: notifications, notification_preferences
  006: audit_log
  007: workflows, workflow_stages, workflow_versions
  008: tasks, task_runs
  009: ws_tickets, rate_limit_counters

Dropped: providers, personas, channels, messages, knowledge, notes,
memory, workspaces, projects, folders, files, usage_log, tool_health,
workflow_assignments, ext_view_channels.

Schema changes vs old:
  - pgvector extension removed (no KB embeddings)
  - resource_grants: resource_type CHECK removed (open-ended)
  - workflow_stages: persona_id kept as nullable TEXT (no FK)
  - workflow_stages: stage_mode default=form_only, added custom
  - tasks: dropped output_channel_id, provider_config_id columns
  - tasks: task_type removed prompt, output_mode: notification|webhook|log
  - task_runs: dropped channel_id
  - platform_policies: kernel-only seeds
  - global_settings: kernel-only seeds, site name=Switchboard Core
  - Everyone group: kernel permissions (extension.use, workflow.submit)

-2815/+487 lines.

server/database/migrations/postgres/002_teams.sql

@@ -0,0 +1,85 @@
+-- ==========================================
+-- Switchboard Core — 002 Teams & Access Control
+-- ==========================================
+
+CREATE TABLE IF NOT EXISTS teams (
+    id          UUID PRIMARY KEY DEFAULT gen_random_uuid(),
+    name        VARCHAR(200) NOT NULL UNIQUE,
+    description TEXT DEFAULT '',
+    created_by  UUID NOT NULL REFERENCES users(id) ON DELETE RESTRICT,
+    is_active   BOOLEAN DEFAULT true,
+    settings    JSONB DEFAULT '{}'::jsonb,
+    created_at  TIMESTAMPTZ DEFAULT NOW(),
+    updated_at  TIMESTAMPTZ DEFAULT NOW()
+);
+
+CREATE INDEX IF NOT EXISTS idx_teams_active ON teams(is_active) WHERE is_active = true;
+DROP TRIGGER IF EXISTS teams_updated_at ON teams;
+CREATE TRIGGER teams_updated_at BEFORE UPDATE ON teams
+    FOR EACH ROW EXECUTE FUNCTION update_updated_at();
+
+CREATE TABLE IF NOT EXISTS team_members (
+    id          UUID PRIMARY KEY DEFAULT gen_random_uuid(),
+    team_id     UUID NOT NULL REFERENCES teams(id) ON DELETE CASCADE,
+    user_id     UUID NOT NULL REFERENCES users(id) ON DELETE CASCADE,
+    role        VARCHAR(20) NOT NULL DEFAULT 'member'
+                CHECK (role IN ('admin', 'member')),
+    joined_at   TIMESTAMPTZ DEFAULT NOW(),
+    UNIQUE(team_id, user_id)
+);
+
+CREATE INDEX IF NOT EXISTS idx_team_members_team ON team_members(team_id);
+CREATE INDEX IF NOT EXISTS idx_team_members_user ON team_members(user_id);
+
+-- ── Groups ──────────────────────────────────
+
+CREATE TABLE IF NOT EXISTS groups (
+    id          UUID PRIMARY KEY DEFAULT gen_random_uuid(),
+    name        VARCHAR(100) NOT NULL,
+    description TEXT NOT NULL DEFAULT '',
+    scope       VARCHAR(20) NOT NULL DEFAULT 'global'
+                CHECK (scope IN ('global', 'team')),
+    team_id     UUID REFERENCES teams(id) ON DELETE CASCADE,
+    created_by  UUID REFERENCES users(id),
+    source      VARCHAR(20) NOT NULL DEFAULT 'manual'
+                CHECK (source IN ('manual', 'oidc', 'system')),
+    permissions          JSONB   NOT NULL DEFAULT '[]'::jsonb,
+    token_budget_daily   BIGINT,
+    token_budget_monthly BIGINT,
+    allowed_models       JSONB,
+    created_at  TIMESTAMPTZ DEFAULT NOW(),
+    updated_at  TIMESTAMPTZ DEFAULT NOW(),
+    CONSTRAINT groups_scope_team CHECK (
+        (scope = 'global' AND team_id IS NULL) OR
+        (scope = 'team' AND team_id IS NOT NULL)
+    )
+);
+
+CREATE UNIQUE INDEX IF NOT EXISTS idx_groups_name_scope
+    ON groups(name, COALESCE(team_id, '00000000-0000-0000-0000-000000000000'));
+DROP TRIGGER IF EXISTS groups_updated_at ON groups;
+CREATE TRIGGER groups_updated_at BEFORE UPDATE ON groups
+    FOR EACH ROW EXECUTE FUNCTION update_updated_at();
+
+CREATE TABLE IF NOT EXISTS group_members (
+    id          UUID PRIMARY KEY DEFAULT gen_random_uuid(),
+    group_id    UUID NOT NULL REFERENCES groups(id) ON DELETE CASCADE,
+    user_id     UUID NOT NULL REFERENCES users(id) ON DELETE CASCADE,
+    added_by    UUID NOT NULL REFERENCES users(id),
+    added_at    TIMESTAMPTZ DEFAULT NOW(),
+    UNIQUE(group_id, user_id)
+);
+
+CREATE INDEX IF NOT EXISTS idx_group_members_group ON group_members(group_id);
+CREATE INDEX IF NOT EXISTS idx_group_members_user ON group_members(user_id);
+
+-- Seed Everyone group
+INSERT INTO groups (id, name, description, scope, created_by, source, permissions)
+VALUES (
+    '00000000-0000-0000-0000-000000000001',
+    'Everyone',
+    'Implicit group — all authenticated users receive these permissions.',
+    'global', NULL, 'system',
+    '["extension.use","workflow.submit"]'::jsonb
+)
+ON CONFLICT (id) DO NOTHING;