feat(13-02): add wireless_links table migration, ORM model, register both models

- Migration 033 creates wireless_links with state machine, missed_polls, RLS
- WirelessLink model with LinkState enum (discovered/active/degraded/down/stale)
- Register DeviceInterface, WirelessLink, LinkState in models __init__

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

backend/alembic/versions/033_wireless_links_table.py

@@ -0,0 +1,109 @@
+"""Create wireless_links table for AP-CPE link state tracking.
+
+Revision ID: 033
+Revises: 032
+Create Date: 2026-03-19
+
+Stores discovered wireless links between AP and CPE devices with
+state machine columns for link health tracking (discovered -> active ->
+degraded -> down -> stale).
+"""
+
+import sqlalchemy as sa
+from alembic import op
+
+revision = "033"
+down_revision = "032"
+branch_labels = None
+depends_on = None
+
+
+def upgrade() -> None:
+    op.create_table(
+        "wireless_links",
+        sa.Column(
+            "id",
+            sa.dialects.postgresql.UUID(as_uuid=True),
+            primary_key=True,
+            server_default=sa.text("gen_random_uuid()"),
+        ),
+        sa.Column(
+            "ap_device_id",
+            sa.dialects.postgresql.UUID(as_uuid=True),
+            sa.ForeignKey("devices.id", ondelete="CASCADE"),
+            nullable=False,
+        ),
+        sa.Column(
+            "cpe_device_id",
+            sa.dialects.postgresql.UUID(as_uuid=True),
+            sa.ForeignKey("devices.id", ondelete="CASCADE"),
+            nullable=False,
+        ),
+        sa.Column(
+            "tenant_id",
+            sa.dialects.postgresql.UUID(as_uuid=True),
+            sa.ForeignKey("tenants.id", ondelete="CASCADE"),
+            nullable=False,
+        ),
+        sa.Column("interface", sa.String(255), nullable=True),
+        sa.Column("client_mac", sa.String(17), nullable=False),
+        sa.Column("signal_strength", sa.Integer, nullable=True),
+        sa.Column("tx_ccq", sa.Integer, nullable=True),
+        sa.Column("tx_rate", sa.String(50), nullable=True),
+        sa.Column("rx_rate", sa.String(50), nullable=True),
+        sa.Column(
+            "state",
+            sa.String(20),
+            nullable=False,
+            server_default=sa.text("'discovered'"),
+        ),
+        sa.Column("missed_polls", sa.Integer, nullable=False, server_default=sa.text("0")),
+        sa.Column(
+            "discovered_at",
+            sa.DateTime(timezone=True),
+            server_default=sa.func.now(),
+            nullable=False,
+        ),
+        sa.Column(
+            "last_seen",
+            sa.DateTime(timezone=True),
+            server_default=sa.func.now(),
+            nullable=False,
+        ),
+        sa.Column(
+            "updated_at",
+            sa.DateTime(timezone=True),
+            server_default=sa.func.now(),
+            nullable=False,
+        ),
+        sa.UniqueConstraint("ap_device_id", "cpe_device_id", name="uq_wireless_links_ap_cpe"),
+    )
+
+    op.create_index("idx_wireless_links_ap", "wireless_links", ["ap_device_id"])
+    op.create_index("idx_wireless_links_cpe", "wireless_links", ["cpe_device_id"])
+    op.create_index("idx_wireless_links_tenant_state", "wireless_links", ["tenant_id", "state"])
+    op.create_index("idx_wireless_links_client_mac", "wireless_links", ["client_mac"])
+
+    # Enable RLS with tenant isolation policy
+    conn = op.get_bind()
+    conn.execute(sa.text("ALTER TABLE wireless_links ENABLE ROW LEVEL SECURITY"))
+    conn.execute(sa.text("ALTER TABLE wireless_links FORCE ROW LEVEL SECURITY"))
+    conn.execute(
+        sa.text("""
+            CREATE POLICY tenant_isolation ON wireless_links
+            USING (
+                tenant_id::text = current_setting('app.current_tenant', true)
+                OR current_setting('app.current_tenant', true) = 'super_admin'
+            )
+            WITH CHECK (
+                tenant_id::text = current_setting('app.current_tenant', true)
+                OR current_setting('app.current_tenant', true) = 'super_admin'
+            )
+        """)
+    )
+
+
+def downgrade() -> None:
+    conn = op.get_bind()
+    conn.execute(sa.text("DROP POLICY IF EXISTS tenant_isolation ON wireless_links"))
+    op.drop_table("wireless_links")