refactor(v2): hoist LP state (wallet, mode, autoforward) into dca_lp table

LP-level preferences were denormalised across every `dca_clients` row
of a given user. Every LP enrolment carried its own wallet_id /
dca_mode / fixed_mode_daily_limit / autoforward_ln_address /
autoforward_enabled — and satmachineclient's `update_lp_autoforward`
did a multi-row UPDATE to keep them in sync. That sync dance was the
smell: user-level intent stored at machine-enrolment granularity.

New shape:

  dca_lp  (user_id PK, dca_wallet_id, default_dca_mode,
           fixed_mode_daily_limit, autoforward_ln_address,
           autoforward_enabled, ...)
  dca_clients  (id, machine_id, user_id, username, status, ...)
        // pure (machine, LP) enrolment — wallet/mode/autoforward gone

Authority split:
  - LP writes dca_lp via satmachineclient (Phase 2, separate commit).
  - Operator writes dca_clients via satmachineadmin. They cannot
    choose the LP's destination wallet — it's resolved from dca_lp
    at distribution time. Better trust hygiene.

Onboarding gate:
  - `api_create_deposit` refuses (HTTP 422) when the target LP has
    no dca_lp row. Forces every LP through a "yes, I am here and
    this is where I want my sats" gesture via satmachineclient
    before any fiat starts accumulating against them.

Schema:
  - m001 canonical schema updated: slim `dca_clients`, new `dca_lp`.
    Fresh installs land here directly.
  - m004 idempotent migration for installs that already have the
    legacy `dca_clients.wallet_id` column: creates dca_lp,
    backfills from the latest dca_clients row per user (window
    function), then DROP COLUMN on the moved fields. Greg's live
    test data survives the upgrade.

Distribution:
  - `get_flow_mode_clients_for_machine` INNER JOINs dca_lp so
    un-onboarded LPs are filtered out (no destination wallet).
  - `_pay_one_dca_leg`, `_attempt_autoforward`, `settle_lp_balance`
    all fetch `dca_lp` via the new `get_dca_lp(user_id)` helper.
    Wallet + autoforward read from prefs, not from client.

Models:
  - `DcaClient` loses 5 fields. `CreateDcaClientData` reduces to
    (machine_id, user_id, username). `UpdateDcaClientData` keeps
    only operator-controlled fields (username, status).
  - New `DcaLpPreferences` + `UpsertDcaLpData` models for the
    per-user surface (satmachineclient writes these in Phase 2).

CRUD:
  - New: `get_dca_lp`, `lp_is_onboarded`, `upsert_dca_lp` (the
    latter takes a `fallback_wallet_id` for first-onboarding when
    satmachineclient auto-seeds from the LP's default LNbits wallet).
  - `create_dca_client` insert reduces to the new column set.

Tests: 86 unit tests still green.

Next:
  - Phase 1c (this repo): UI simplification for operator's
    Add/Edit LP dialogs + deposit-gating UX.
  - Phase 2 (satmachineclient): own dca_lp writes + auto-init with
    the LP's default LNbits wallet on first dashboard visit.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

views_api.py

@@ -39,6 +39,7 @@ from .crud import (
     get_settlements_for_operator,
     get_stuck_settlements_for_operator,
     get_super_config,
+    lp_is_onboarded,
     replace_commission_splits,
     reset_settlement_for_retry,
     update_dca_client,
@@ -311,6 +312,18 @@ async def api_create_deposit(
             HTTPStatus.BAD_REQUEST,
             "client_id and machine_id refer to different machines",
         )
+    # Gate: refuse deposits for an LP who hasn't onboarded via
+    # satmachineclient. Without a dca_lp row we don't know where to
+    # send their DCA distributions, so accepting fiat against them
+    # would just queue up sats with nowhere to go. Forces the LP to
+    # actively register before any economic activity accrues.
+    if not await lp_is_onboarded(client.user_id):
+        raise HTTPException(
+            HTTPStatus.UNPROCESSABLE_ENTITY,
+            "LP has not onboarded yet — they must register via "
+            "satmachineclient and select a DCA wallet before deposits "
+            "can be recorded against them.",
+        )
     return await create_deposit(user.id, data)