orm: deprecate global tenant filter APIs, deadline 2027-06-08 (#27389)

* orm: deprecate global tenant filter APIs, deadline 2027-06-08

The old global tenant filter mechanism (configure_tenant_filter,
set_current_tenant_id, with_tenant, without_tenant_filter, etc.)
is replaced by the per-instance DataScope / orm.DB pattern.
Add @[deprecated] and @[deprecated_after] attributes to all 10
public items so users get a notice directing them to the new API.

See: PR #27324 (DataScope support)

* orm: remove deprecation from apply_tenant_filter (still used by DB backends)

apply_tenant_filter is an internal helper called by the sqlite, mysql,
and pg ORM backends in their select/update/delete paths. Marking it
@[deprecated] would produce notices in every ORM-backed build and
become a hard error after the grace period, breaking the backends.

Keeps the 9 user-facing APIs deprecated as-is.

* orm: deprecate apply_tenant_filter (covers remaining global-tenant public API point)

* orm: remove deprecation from apply_tenant_filter (still used by DB backends)

The apply_tenant_filter function is internal plumbing still used by
db/sqlite, db/pg, and db/mysql backends. Deprecating it with -W in CI
causes every tool that imports db/sqlite or any .vv test that imports
it to fail.

Keeps the other 9 deprecation markers (TenantFilterConfig,
configure_tenant_filter, set_tenant_filter_enabled,
set_current_tenant_id, clear_current_tenant_id, with_tenant,
with_tenant_value, without_tenant_filter,
without_tenant_filter_value).

Fixes all 19 CI failures in PR #27389.

Author: Jengro777

vlib/orm/orm.v

@@ -298,6 +298,8 @@ struct TenantFilterScopeState {
 	current_tenant     Primitive
 }
 
+@[deprecated: 'use `orm.DataScope` and `orm.new_db()` for per-instance request-level filtering']
+@[deprecated_after: '2027-06-08']
 pub struct TenantFilterConfig {
 pub:
 	enabled    bool   = true
@@ -343,17 +345,23 @@ mut:
 }
 
 // configure_tenant_filter configures the global ORM tenant filter behavior.
+@[deprecated: 'use `orm.DataScope` and `orm.new_db()` for per-instance request-level filtering']
+@[deprecated_after: '2027-06-08']
 pub fn configure_tenant_filter(config TenantFilterConfig) {
 	tenant_filter_state.enabled = config.enabled
 	tenant_filter_state.field_name = normalize_tenant_filter_field_name(config.field_name)
 }
 
 // set_tenant_filter_enabled enables or disables global tenant filtering.
+@[deprecated: 'use `orm.DataScope` and `orm.new_db()` for per-instance request-level filtering']
+@[deprecated_after: '2027-06-08']
 pub fn set_tenant_filter_enabled(enabled bool) {
 	tenant_filter_state.enabled = enabled
 }
 
 // set_current_tenant_id sets the current tenant id used by global tenant filtering.
+@[deprecated: 'use `orm.DataScope` and `orm.new_db()` for per-instance request-level filtering']
+@[deprecated_after: '2027-06-08']
 pub fn set_current_tenant_id(tenant_id Primitive) {
 	if tenant_id is Null {
 		clear_current_tenant_id()
@@ -364,12 +372,16 @@ pub fn set_current_tenant_id(tenant_id Primitive) {
 }
 
 // clear_current_tenant_id clears the current tenant id used by global tenant filtering.
+@[deprecated: 'use `orm.DataScope` and `orm.new_db()` for per-instance request-level filtering']
+@[deprecated_after: '2027-06-08']
 pub fn clear_current_tenant_id() {
 	tenant_filter_state.has_current_tenant = false
 	tenant_filter_state.current_tenant = null_primitive
 }
 
 // with_tenant executes `callback` with a temporary tenant id and enabled tenant filtering.
+@[deprecated: 'use `orm.DataScope` and `orm.new_db()` for per-instance request-level filtering']
+@[deprecated_after: '2027-06-08']
 pub fn with_tenant[T](tenant_id Primitive, callback fn () !T) !T {
 	saved := tenant_filter_scope_snapshot()
 	tenant_filter_state.enabled = true
@@ -382,6 +394,8 @@ pub fn with_tenant[T](tenant_id Primitive, callback fn () !T) !T {
 }
 
 // with_tenant_value executes `callback` with a temporary tenant id and enabled tenant filtering.
+@[deprecated: 'use `orm.DataScope` and `orm.new_db()` for per-instance request-level filtering']
+@[deprecated_after: '2027-06-08']
 pub fn with_tenant_value[T](tenant_id Primitive, callback fn () T) T {
 	saved := tenant_filter_scope_snapshot()
 	tenant_filter_state.enabled = true
@@ -394,6 +408,8 @@ pub fn with_tenant_value[T](tenant_id Primitive, callback fn () T) T {
 }
 
 // without_tenant_filter executes `callback` with tenant filtering temporarily disabled.
+@[deprecated: 'use `orm.DB.unscoped()` for per-instance scope bypass']
+@[deprecated_after: '2027-06-08']
 pub fn without_tenant_filter[T](callback fn () !T) !T {
 	saved := tenant_filter_scope_snapshot()
 	tenant_filter_state.enabled = false
@@ -404,6 +420,8 @@ pub fn without_tenant_filter[T](callback fn () !T) !T {
 }
 
 // without_tenant_filter_value executes `callback` with tenant filtering temporarily disabled.
+@[deprecated: 'use `orm.DB.unscoped()` for per-instance scope bypass']
+@[deprecated_after: '2027-06-08']
 pub fn without_tenant_filter_value[T](callback fn () T) T {
 	saved := tenant_filter_scope_snapshot()
 	tenant_filter_state.enabled = false