fix(seed): guarantee every displayed month of Monthly Revenue is in-band

[jeffgicharu]

Problem

The dashboard Monthly Revenue chart aggregates paid invoices by paid_at
month over the trailing 6 months (DashboardRepository.getMonthlyRevenue). The
seed's random invoice distribution is realistic for project-based billing but,
on some reseeds, left the oldest displayed month at $0 — its paid_at
spilling just outside the dashboard window. The chart then read as a ramp-up
from zero rather than an established business, and varied per reseed.

Live "before" (current production seed) — Dec starts at ~$0, May trails to ~$0:

Month	Dec	Jan	Feb	Mar	Apr	May
Old seed (reseed sample)	$0–$15k	~$58k	~$30k	~$32k	low	~$0

Fix

Deterministically plant a paid-invoice baseline in each of the 6 displayed
months, layered on top of the existing random invoices. Each month's baseline
paid_at is pinned to the 15th at noon UTC (clamped into the past) so it
always lands in that month's date_trunc('month') bucket and inside the
dashboard window. The baseline amounts are fixed (no RNG), so the floor is
guaranteed on every reseed.

Determinism approach (one sentence): the seed plants two fixed-amount paid
invoices per displayed month, dated to mid-month in the past, before the random
invoices are layered on — so every month's total is deterministically above the
floor regardless of the random draw.

Chosen band (documented in seed.ts):

• Floor: $40,000 — every displayed month is comfortably nonzero.
• Ceiling: $200,000 — baseline ($50–64k) plus random top-up stays well
  under this; observed reseed totals land **$54k–$126k**, current month never a
  spike (consistent with fix(seed): revenue chart should not spike on the current month #37).

After (4 consecutive reseeds, all 6 months in-band):

Reseed	Dec	Jan	Feb	Mar	Apr	May
1	81,556	61,211	84,036	67,983	122,774	54,400
2	103,121	71,297	125,961	59,300	120,280	70,246
3	111,883	95,210	105,539	96,062	89,424	64,526
4	80,816	118,877	78,245	87,048	103,116	55,795

Test

New Postgres-backed regression test dashboard-revenue.int-spec.ts runs the
demo seed against a fresh database, calls the exact dashboard aggregation, and
asserts every month in the 6-month window is > 0 and within [40k, 200k].
Verified it fails on the pre-baseline seed (3/3 runs, a month at
~$12k–$31k) and passes after (4/4 runs).

The chart component is unchanged; no months are hidden — data is guaranteed,
not its absence masked.

Scope

Touches only the invoice seed for the displayed revenue window and the new
test. No other settled data (compliance, audit, W-9, currency, names,
classification, risk weights) is modified.

[gemini-code-assist]

Code Review

This pull request introduces a deterministic revenue baseline within the demoSeed function to ensure the dashboard's monthly revenue chart consistently displays data for the trailing six months. It also includes a new integration test to verify that the seeded revenue remains within the expected $40,000 to $200,000 range. Feedback was provided regarding an inefficient UPDATE query in the seeding logic that could lead to NULL values for total_amount if tax_amount is not set, potentially defeating the purpose of the baseline fix. A more robust and optimized query was suggested.

[gemini-code-assist]

The UPDATE query is inefficient as it executes the same subquery twice for every baseline invoice. More importantly, if tax_amount is NULL in the database (which is likely since it is not specified in the preceding INSERT statement), the total_amount calculation (subtotal + tax_amount) will result in NULL. This would cause the dashboard revenue aggregation to return 0 for that month, defeating the purpose of this baseline fix. Since we know the subtotal for these specific baseline invoices is exactly perInvoice, we can optimize the query and use COALESCE to ensure the total is correctly calculated.

          await pool.query(
            `UPDATE invoices SET
              subtotal = $2,
              total_amount = $2 + COALESCE(tax_amount, 0)
             WHERE id = $1`,
            [invId, perInvoice],
          );

[jeffgicharu]

Live verification complete. Backed up the production DB to /var/backups/contractoros-pre-chart-lockdown-20260519-063959.sql, reseeded production, and read the live dashboard. The Monthly Revenue chart now shows six nonzero, bumpy months sitting steady in the ~$90k–$120k range (Mar $107,576) — no zero start at Dec, no collapse at May, Y-axis tops at $120k well under the $200k ceiling.