Order and line item naming templates not applied consistently

[estofko-scope3]

Custom naming templates configured in tenant policy settings are ignored by the GAM adapter. Instead, the GAM adapter reads from AdapterConfig fields which are never populated by the policy settings UI.

Example:
Configured template (in tenant policies): {brand_name} - {buyer_ref}

Expected order name: Acme Corp - mb_x2ypSo_OTE

Actual order name: Campaign mb_x2ypSo_OTE - Feb 09-28, 2026 [mb_x2ypSo_OTE]

The actual name uses the default template {campaign_name|brand_name} - {date_range} because the custom template is stored in Tenant.order_name_template but the GAM adapter reads from AdapterConfig.gam_order_name_template.

Root Cause:
Configuration disconnect between Tenant and AdapterConfig
GAM adapter reads from AdapterConfig (lines 623-625, google_ad_manager.py):

if adapter_config.gam_order_name_template:
    order_name_template = adapter_config.gam_order_name_template

But policy settings UI writes to Tenant (lines 371-375, policy_service.py):

if "order_name_template" in updates:
    tenant.order_name_template = updates["order_name_template"]

[jrosendahl-opt]

Root cause is code duplication. Duplication must be addressed as a part of this issue.

[ChrisHuie]

Re-traced on current main — this still reproduces, and the scope is a bit wider than the
original description. Refreshed file:line references below (the ones in the issue body have
shifted).

The disconnect

• GAM reads the template from AdapterConfig.gam_*_name_template: adapter_helpers.py:146
  (get_gam_naming_templates) → google_ad_manager.py:165.
• The policy / tenant settings UI writes Tenant.*_name_template: policy_service.py:371.
• The Mock adapter reads Tenant.order_name_template (mock_ad_server.py:761) — so the two
  adapters read different columns.
• Net: a template set in Tenant/Policy Settings is honored by Mock but ignored by GAM.
  Tenant.order_name_template is even commented "shared across all adapters"
  (models.py:104), which GAM contradicts.

On the duplication

• The default {campaign_name|brand_name} - {media_buy_id} - {date_range} is copy-pasted in
  five places with no shared constant: workflow.py:154, google_ad_manager.py:623,
  mock_ad_server.py:754, models.py:106, policy_service.py:70.
• Those copies have already drifted: the line-item fallback is {product_name}
  (orders.py:394) vs {order_name} - {product_name} on the column/policy, and the admin UI
  shows a third default {campaign_name|promoted_offering} - {date_range}
  (tenant_settings.html:1369).
• There's also a fully dead third store: product-level order_name_template in
  gam_implementation_config_schema.py:56 (+ presets) has no write path and no read path in
  current code.

Suggested direction
Single source of truth = Tenant.*_name_template, read identically by every adapter, with one
shared default constant; drop AdapterConfig.gam_*_name_template (backfilling any non-null
values into Tenant.* first). De-risk: GAM is the only production reader of the GAM columns
(adapter_helpers.py:146), and a tenant runs exactly one adapter at a time (tenant.ad_server
is singular), so per-adapter template columns aren't needed.

Test gap
No test asserts GAM honors a policy-configured template, and
test_adapter_config_repository.py:237 currently pins the AdapterConfig-as-source behavior. A
fix should add an integration test that sets a template and asserts the resulting GAM
order/line-item name.

Related
Same defect class as #1516 — a configured value (there, native_style_id) is written but never
read at execution. Grouped under the tracking issue #1530.

[jrosendahl-opt]

Investigate all of the naming convention spots and make sure the are the same.