feat(ads): server-driven ad-banner backend, wire & admin console (PR1)

Turn the gated-off mock banner into a real advertising subsystem (backend +
admin half; the UI rotation lands in PR2).

- internal/ads: campaigns (percent weight + validity window; a perpetual,
  undeletable default that fills the remainder up to 100%), 1..N bilingual
  messages (en+ru), global display timings; ActiveSet computes the
  window-filtered, default-remainder, GCD-reduced, language-resolved rotation
  feed. Smooth-weighted-round-robin math is unit-tested.
- migration 00006 (+ jetgen): ad_campaigns / ad_messages / ad_settings, seeded
  default campaign + house message + default timings.
- eligibility = !paid_account && hint_balance==0 && !no_banner role (new role;
  guests qualify). The resolved feed rides the profile.get response (no new RPC,
  works for guests, nothing distinct to filter); language by service_language.
- live update: a notify `banner` sub-kind (re-poll signal) published when an
  operator grants hints or grants/revokes no_banner, so the client shows/hides
  in place.
- admin console /_gm/banners (+ /_gm/banner-settings): campaign + message CRUD
  with reorder, default protection, clamped timings.
- wire: fbs BannerInfo/BannerCampaign on Profile; gateway transcode forwards it.
- docs: ARCHITECTURE §10, FUNCTIONAL (+ _ru), backend README, PRERELEASE tracker
  (incl. the deferred app.load aggregator note).

backend/internal/postgres/jet/backend/table/ad_campaigns.go

@@ -0,0 +1,102 @@
+//
+// Code generated by go-jet DO NOT EDIT.
+//
+// WARNING: Changes to this file may cause incorrect behavior
+// and will be lost if the code is regenerated
+//
+
+package table
+
+import (
+	"github.com/go-jet/jet/v2/postgres"
+)
+
+var AdCampaigns = newAdCampaignsTable("backend", "ad_campaigns", "")
+
+type adCampaignsTable struct {
+	postgres.Table
+
+	// Columns
+	CampaignID postgres.ColumnString
+	Name       postgres.ColumnString
+	Weight     postgres.ColumnInteger
+	IsDefault  postgres.ColumnBool
+	Enabled    postgres.ColumnBool
+	StartsAt   postgres.ColumnTimestampz
+	EndsAt     postgres.ColumnTimestampz
+	CreatedAt  postgres.ColumnTimestampz
+	UpdatedAt  postgres.ColumnTimestampz
+
+	AllColumns     postgres.ColumnList
+	MutableColumns postgres.ColumnList
+	DefaultColumns postgres.ColumnList
+}
+
+type AdCampaignsTable struct {
+	adCampaignsTable
+
+	EXCLUDED adCampaignsTable
+}
+
+// AS creates new AdCampaignsTable with assigned alias
+func (a AdCampaignsTable) AS(alias string) *AdCampaignsTable {
+	return newAdCampaignsTable(a.SchemaName(), a.TableName(), alias)
+}
+
+// Schema creates new AdCampaignsTable with assigned schema name
+func (a AdCampaignsTable) FromSchema(schemaName string) *AdCampaignsTable {
+	return newAdCampaignsTable(schemaName, a.TableName(), a.Alias())
+}
+
+// WithPrefix creates new AdCampaignsTable with assigned table prefix
+func (a AdCampaignsTable) WithPrefix(prefix string) *AdCampaignsTable {
+	return newAdCampaignsTable(a.SchemaName(), prefix+a.TableName(), a.TableName())
+}
+
+// WithSuffix creates new AdCampaignsTable with assigned table suffix
+func (a AdCampaignsTable) WithSuffix(suffix string) *AdCampaignsTable {
+	return newAdCampaignsTable(a.SchemaName(), a.TableName()+suffix, a.TableName())
+}
+
+func newAdCampaignsTable(schemaName, tableName, alias string) *AdCampaignsTable {
+	return &AdCampaignsTable{
+		adCampaignsTable: newAdCampaignsTableImpl(schemaName, tableName, alias),
+		EXCLUDED:         newAdCampaignsTableImpl("", "excluded", ""),
+	}
+}
+
+func newAdCampaignsTableImpl(schemaName, tableName, alias string) adCampaignsTable {
+	var (
+		CampaignIDColumn = postgres.StringColumn("campaign_id")
+		NameColumn       = postgres.StringColumn("name")
+		WeightColumn     = postgres.IntegerColumn("weight")
+		IsDefaultColumn  = postgres.BoolColumn("is_default")
+		EnabledColumn    = postgres.BoolColumn("enabled")
+		StartsAtColumn   = postgres.TimestampzColumn("starts_at")
+		EndsAtColumn     = postgres.TimestampzColumn("ends_at")
+		CreatedAtColumn  = postgres.TimestampzColumn("created_at")
+		UpdatedAtColumn  = postgres.TimestampzColumn("updated_at")
+		allColumns       = postgres.ColumnList{CampaignIDColumn, NameColumn, WeightColumn, IsDefaultColumn, EnabledColumn, StartsAtColumn, EndsAtColumn, CreatedAtColumn, UpdatedAtColumn}
+		mutableColumns   = postgres.ColumnList{NameColumn, WeightColumn, IsDefaultColumn, EnabledColumn, StartsAtColumn, EndsAtColumn, CreatedAtColumn, UpdatedAtColumn}
+		defaultColumns   = postgres.ColumnList{IsDefaultColumn, EnabledColumn, CreatedAtColumn, UpdatedAtColumn}
+	)
+
+	return adCampaignsTable{
+		Table: postgres.NewTable(schemaName, tableName, alias, allColumns...),
+
+		//Columns
+		CampaignID: CampaignIDColumn,
+		Name:       NameColumn,
+		Weight:     WeightColumn,
+		IsDefault:  IsDefaultColumn,
+		Enabled:    EnabledColumn,
+		StartsAt:   StartsAtColumn,
+		EndsAt:     EndsAtColumn,
+		CreatedAt:  CreatedAtColumn,
+		UpdatedAt:  UpdatedAtColumn,
+
+		AllColumns:     allColumns,
+		MutableColumns: mutableColumns,
+		DefaultColumns: defaultColumns,
+	}
+}