fix: add 404 catch-all page

[Alchez]

Closes #214

[github-actions]

Coverage Report

File	Stmts	Miss	Cover	Missing
__init__.py	1	0	100%
beam
barcodes.py	31	13	58%	18, 27, 29, 32, 43–44, 46–47, 52–54, 58–59
handling_unit.py	81	37	54%	25, 31, 63–65, 83, 94–95, 101–102, 104–105, 107–108, 110–111, 113, 115–118, 120–122, 124, 126, 128–129, 134, 136, 140, 142–143, 146, 148–149, 157
printing.py	61	61	0%	4–6, 8, 11–12, 15–16, 18–21, 24–25, 34–45, 47–54, 58–59, 61–62, 71–75, 78–79, 85–87, 90–91, 94–95, 97–99, 101–102, 104, 109, 111–112
beam/demand
demand.py	322	77	76%	51, 66, 123, 209, 243, 290, 293, 425–426, 428–429, 432–433, 435, 439–444, 446, 448–449, 452, 457, 459–464, 466, 468, 471, 474, 479, 483–485, 490–491, 493, 495–497, 499, 505, 507–510, 512–515, 517, 519, 522–523, 525–526, 529, 543, 560–561, 563–565, 621, 625, 662, 667, 674, 695–696, 708, 837
receiving.py	111	4	96%	79, 131, 173, 214
sqlite.py	59	1	98%	40
utils.py	59	7	88%	56, 67, 72–75, 83
beam/doctype/beam_mobile_route
beam_mobile_route.py	3	0	100%
beam/doctype/beam_settings
beam_settings.py	28	17	39%	31–33, 36–37, 39, 46, 51–54, 62–64, 68–70
beam/doctype/handling_unit
__init__.py	9	3	66%	12–14
handling_unit.py	15	0	100%
beam/doctype/warehouse_types
warehouse_types.py	3	0	100%
beam/overrides
sales_order.py	10	6	40%	11–16
stock_entry.py	67	17	74%	61–62, 67–74, 80–81, 97, 112, 129, 132–133
work_order.py	10	2	80%	14, 16
beam/report/demand_map
demand_map.py	35	35	0%	4–5, 7–8, 11–12, 15–16, 103–111, 127, 129–143, 146–147
beam/report/handling_unit_traceability
handling_unit_traceability.py	44	44	0%	4–6, 9–11, 30–32, 34–35, 37–38, 41–42, 45–46, 48–49, 51–52, 54–55, 57, 63–65, 67–69, 71, 74–77, 79–81, 83–86, 89–90
beam/scan
__init__.py	132	22	83%	21, 25, 30, 38, 70, 117–118, 128, 130–131, 135, 139–140, 143, 154–155, 159, 180, 209, 211, 229, 232
config.py	26	26	0%	4, 6, 9–17, 19–21, 23–26, 28–30, 32–35, 37
www/beam
__init__.py	14	14	0%	4–7, 10–19
index.py	7	7	0%	4, 6, 9–13
TOTAL	1128	393	65%