analytics: your share of what someone else paid is your spend

Every spend analytic gated on `OWNER_SCOPE = $1` and scaled by `mySplitOf`
*within* that gate, so ownership was a precondition for an expense being
yours. Half a grocery shop Sonu paid for counted as zero — in monthly,
daily, merchants, subscriptions, fees and the budget page. 167 rows /
$3,210.91 across Jan-Jul 2026, worst in April (+$1,354.83, the Europe
trips), while getParticipantBalances booked the matching debt correctly.
The app could say you owed her for a shop while insisting you had not
spent anything on it.

New MY_SPEND_SCOPE(): owner = me OR I hold a split. OWNER_SCOPE stays on
the things that measure an *account* rather than a person — the income
and investment lines, and the statement-level fee rollup.

myShare had to change with it, and widening the gate alone would have
been worse than the bug: its `100 - everyone else` fallback is the
payer's remainder, so on someone else's unsplit row it returns 100 and
moves their whole bill onto you. It now branches on ownership — my row
resolves as before; their row takes an explicit split row only, absent
meaning 0. That 0 is what makes the wider gate safe.

my_share_percent is deliberately not read on someone else's row: one
unscoped column, writable by anyone who can see the row, so "my" can
only mean the owner's. All 402 rows carrying one today are owner-side.

MY_SHARE_PCT mirrors myShare for the transactions list, which has no
viewer-scoped ts join; a test asserts the two agree across seven fixture
shapes.

No historical restatement — every non-owner split is 2026-dated, and the
1,266 pre-2026 SplitMyExpenses splits are all on rows you own.

Also fixes a latent failure in the NATIVE_CURRENCY test, which inserted a
statement relying on participant id 1 existing (owner_id is NOT NULL
DEFAULT 1 with an FK) and only passed when a sibling file had left one
behind. It now owns its fixture.

15 new integration tests; 189 integration + 130 unit green.

src/app/api/analytics/merchants/[merchant]/route.ts

@@ -1,7 +1,7 @@
 import { NextRequest, NextResponse } from "next/server";
 import { getCurrentUser } from "@/lib/auth";
 import { queryRaw } from "@/lib/db";
-import { OWNER_SCOPE, STATEMENTS_JOIN, EXCLUDE_RECONCILED_SOURCE, EFFECTIVE_CATEGORY, mySplitOf } from "@/lib/analytics-sql";
+import { MY_SPEND_SCOPE, STATEMENTS_JOIN, EXCLUDE_RECONCILED_SOURCE, EFFECTIVE_CATEGORY, mySplitOf } from "@/lib/analytics-sql";
 import { bankLabel } from "@/lib/queries";
 
 const MY_AMOUNT = mySplitOf(`COALESCE(t.amount_aud, t.amount)`);
@@ -46,7 +46,7 @@ export async function GET(
     ${STATEMENTS_JOIN}
     LEFT JOIN transaction_overrides o ON o.transaction_id = t.id
     LEFT JOIN transaction_splits ts ON ts.transaction_id = t.id AND ts.participant_id = $1
-    WHERE ${OWNER_SCOPE} = $1
+    WHERE ${MY_SPEND_SCOPE()}
       AND t.transaction_type IN ('debit', 'fee', 'interest', 'refund', 'credit')
       AND COALESCE(o.merchant_normalized, t.merchant_normalized, t.merchant_name, t.description) = $2
       AND ${EXCLUDE_RECONCILED_SOURCE}

src/app/api/analytics/merchants/route.ts

@@ -1,7 +1,7 @@
 import { NextRequest, NextResponse } from "next/server";
 import { getCurrentUser } from "@/lib/auth";
 import { queryRaw } from "@/lib/db";
-import { OWNER_SCOPE, STATEMENTS_JOIN, EXCLUDE_NON_SPEND, EXCLUDE_RECONCILED_SOURCE, EFFECTIVE_CATEGORY, mySplitOf, toDateStr } from "@/lib/analytics-sql";
+import { MY_SPEND_SCOPE, STATEMENTS_JOIN, EXCLUDE_NON_SPEND, EXCLUDE_RECONCILED_SOURCE, EFFECTIVE_CATEGORY, mySplitOf, toDateStr } from "@/lib/analytics-sql";
 
 // Split-adjusted amount helper (positive for spend, negative for refunds)
 const MY_AMOUNT = mySplitOf(`COALESCE(t.amount_aud, t.amount)`);
@@ -65,7 +65,7 @@ export async function GET(req: NextRequest) {
     ${STATEMENTS_JOIN}
     LEFT JOIN transaction_overrides o ON o.transaction_id = t.id
     LEFT JOIN transaction_splits ts ON ts.transaction_id = t.id AND ts.participant_id = $1
-    WHERE ${OWNER_SCOPE} = $1
+    WHERE ${MY_SPEND_SCOPE()}
       AND t.transaction_type IN ('debit', 'fee', 'interest', 'refund', 'credit')
       AND t.transaction_date >= $2
       AND ${EXCLUDE_NON_SPEND}
@@ -91,7 +91,7 @@ export async function GET(req: NextRequest) {
       ${STATEMENTS_JOIN}
       LEFT JOIN transaction_overrides o ON o.transaction_id = t.id
       LEFT JOIN transaction_splits ts ON ts.transaction_id = t.id AND ts.participant_id = $1
-      WHERE ${OWNER_SCOPE} = $1
+      WHERE ${MY_SPEND_SCOPE()}
         AND t.transaction_type IN ('debit', 'fee', 'interest', 'refund', 'credit')
         AND t.transaction_date >= $2
         AND COALESCE(o.merchant_normalized, t.merchant_normalized, t.merchant_name, t.description) = ANY($3)