Add regenerateCookieBannerTrackerPolicy mutation

Expose a non-destructive re-trigger that re-arms tracker policy
generation for a banner that already has a published version, so the
tracker-policy worker regenerates the document after iterating on the
generator. RegenerateTrackerPolicy returns a conflict when nothing has
been published yet.

Wire it across all API surfaces per the api-surface rule: the console
GraphQL mutation and resolver, the MCP tool, the prb cookie-banner
regenerate-policy command, and the n8n operation, with console e2e
coverage for the success and no-published-version paths.

Signed-off-by: Émile Ré <emile@probo.com>

pkg/server/api/console/v1/graphql/cookie_banner.graphql

@@ -607,6 +607,9 @@ extend type Mutation {
     publishCookieBannerVersion(
         input: PublishCookieBannerVersionInput!
     ): PublishCookieBannerVersionPayload!
+    regenerateCookieBannerTrackerPolicy(
+        input: RegenerateCookieBannerTrackerPolicyInput!
+    ): RegenerateCookieBannerTrackerPolicyPayload!
     createCookieCategory(
         input: CreateCookieCategoryInput!
     ): CreateCookieCategoryPayload!
@@ -682,6 +685,10 @@ input PublishCookieBannerVersionInput {
     cookieBannerId: ID!
 }
 
+input RegenerateCookieBannerTrackerPolicyInput {
+    cookieBannerId: ID!
+}
+
 input CreateCookieCategoryInput {
     cookieBannerId: ID!
     name: String!
@@ -733,6 +740,10 @@ type PublishCookieBannerVersionPayload {
     cookieBanner: CookieBanner!
 }
 
+type RegenerateCookieBannerTrackerPolicyPayload {
+    cookieBanner: CookieBanner!
+}
+
 type CreateCookieCategoryPayload {
     cookieCategoryEdge: CookieCategoryEdge!
     cookieBanner: CookieBanner!