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>

tests/reddit-account-runtime.test.ts

@@ -240,6 +240,7 @@ describe('account runtime isolation', () => {
         conversationAutomation: { hasActionableReplies },
         chatService: { getInvitationCooldown: () => null },
         rateLimiter: { getTimers: () => ({ nextMessageAvailableAt: null }) },
+        establishmentService: { isSendable: () => true },
       } as unknown as RedditAccountRuntimeResources,
       { start: vi.fn(), stop: vi.fn() },
     );
@@ -250,6 +251,37 @@ describe('account runtime isolation', () => {
     expect(await runtime.canAcceptPost()).toBe(true);
   });
 
+  it('does not accept new outreach while the account is not established yet', async () => {
+    const stored = account('too_new');
+    const isSendable = vi.fn().mockReturnValue(false);
+    const runtime = new RedditAccountRuntime(
+      {
+        accountId: stored.accountId,
+        redditUsername: stored.redditUsername,
+        matrixUserId: stored.matrixUserId!,
+        cookies: [],
+        matrixCredentials: JSON.parse(stored.matrixCredentialsJson),
+        updatedAt: stored.updatedAt,
+      },
+      {
+        accountAuth: {
+          isFullyAuthenticated: () => true,
+          ensureFullyAuthenticated: async () => true,
+        },
+        conversationAutomation: { hasActionableReplies: vi.fn().mockResolvedValue(false) },
+        chatService: { getInvitationCooldown: () => null },
+        rateLimiter: { getTimers: () => ({ nextMessageAvailableAt: null }) },
+        establishmentService: { isSendable },
+      } as unknown as RedditAccountRuntimeResources,
+      { start: vi.fn(), stop: vi.fn() },
+    );
+    await runtime.start();
+
+    expect(await runtime.canAcceptPost()).toBe(false);
+    isSendable.mockReturnValue(true);
+    expect(await runtime.canAcceptPost()).toBe(true);
+  });
+
   it('uses the Reddit fullname for auth while retaining the Matrix runtime owner', () => {
     expect(runtimeAuthenticatedAccount(
       { matrixUserId: '@t2_1u57iqxxbv:reddit.com' },