feat(v2)(ui): operator-side LP UI matches the new dca_lp authority split

Operator no longer chooses the LP's wallet / DCA mode / autoforward —
those belong to the LP, written via satmachineclient. The Add LP /
Edit LP dialogs reduce to (machine, user_id, optional username,
status). The clients table loses the wallet / mode / autoforward
columns and gains an "Onboarded" column showing whether the LP has a
`dca_lp` row yet (server-side LEFT JOIN; `DcaClient.lp_onboarded`).

Deposit creation gate (the structural enforcement of "must onboard
first"):
- Picker annotates each LP option with "— pending onboarding" and
  disables un-onboarded LP rows.
- Selecting an un-onboarded LP shows an inline deep-orange banner
  explaining the LP needs to open satmachineclient once.
- The Record button is `:disable`d in that state. The backend
  refuses with HTTP 422 anyway (see previous commit) — UI is just
  the first line of feedback.

Backend wiring:
- `DcaClient` model gains `lp_onboarded: bool = False`, populated
  at SELECT time via a shared `_CLIENT_SELECT` / `_CLIENT_FROM`
  fragment that LEFT JOINs `dca_lp` on `user_id`. All four list/
  single-row read paths use it: by-id, by-(machine,user), by-machine,
  by-operator, by-user. No extra round-trip per row.
- CSV export drops the removed columns; adds `lp_onboarded`.

All 86 unit tests still pass.

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

models.py

@@ -102,6 +102,10 @@ class DcaClient(BaseModel):
     status: str
     created_at: datetime
     updated_at: datetime
+    # Computed at SELECT time via LEFT JOIN on dca_lp. Lets the operator
+    # UI render "pending onboarding" badges and disable deposit creation
+    # without a second round-trip per row.
+    lp_onboarded: bool = False
 
 
 class UpdateDcaClientData(BaseModel):