feat: flag accounts Reddit considers unestablished and re-test them

New accounts cannot start chats until Reddit considers them established.
Until now the bot would burn a candidate on every invitation Reddit was
always going to reject, with nothing in the dashboard explaining why the
account looked idle.

Two signals feed the verdict. A periodic profile check reads the
account's own age, karma and email verification from about.json and
compares them against configurable thresholds — that is what flags a
brand new account before it wastes anything. A rejected invitation is
authoritative: Reddit has told us directly, so the account is held out of
sending with a backoff that doubles per rejection, and a delivered
invitation clears the flag outright.

An unestablished account takes no new posts (canAcceptPost), raises an
attention item, reports an `unestablished` sending state, and shows its
age/karma evidence on the Accounts page. An unchecked account is always
allowed through, so a first run is never blocked.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

packages/api-contracts/src/session.ts

@@ -6,6 +6,24 @@ export const RedditSessionStateSchema = z.union([
   z.literal('login-required'),
   z.literal('unreachable'),
 ]);
+export const AccountEstablishmentStateSchema = z.union([
+  z.literal('unknown'),
+  z.literal('established'),
+  z.literal('unestablished'),
+]);
+export const AccountEstablishmentSummarySchema = z.strictObject({
+  state: AccountEstablishmentStateSchema,
+  reasons: z.array(z.string()),
+  accountAgeDays: z.number().nullable(),
+  linkKarma: z.number().nullable(),
+  commentKarma: z.number().nullable(),
+  totalKarma: z.number().nullable(),
+  hasVerifiedEmail: z.boolean().nullable(),
+  profileCheckedAt: z.number().nullable(),
+  lastProbeAt: z.number().nullable(),
+  lastProbeFailure: z.string().nullable(),
+  retryAt: z.number().nullable(),
+});
 export const RedditAccountSummarySchema = z.strictObject({
   accountId: z.string().min(1),
   redditUsername: z.string().min(1),
@@ -15,6 +33,8 @@ export const RedditAccountSummarySchema = z.strictObject({
   createdAt: z.number(),
   updatedAt: z.number(),
   lastImportedAt: z.number(),
+  /** Absent on responses from a build that predates establishment tracking. */
+  establishment: AccountEstablishmentSummarySchema.nullable().optional(),
 });
 export const RedditAccountOwnerSchema = RedditAccountSummarySchema.pick({
   accountId: true,
@@ -71,4 +91,6 @@ export type RedditSessionState = z.infer<typeof RedditSessionStateSchema>;
 export type LoginStatusResponse = z.infer<typeof LoginStatusResponseSchema>;
 export type RedditCookieImportRequest = z.infer<typeof RedditCookieImportRequestSchema>;
 export type RedditAccountSummary = z.infer<typeof RedditAccountSummarySchema>;
+export type AccountEstablishmentState = z.infer<typeof AccountEstablishmentStateSchema>;
+export type AccountEstablishmentSummary = z.infer<typeof AccountEstablishmentSummarySchema>;
 export type RedditAccountOwner = z.infer<typeof RedditAccountOwnerSchema>;