fix(server): keep local authorization failures from disabling chat endpoints (#16138)

## Thinking Path

> - Paperclip is the open source app people use to manage AI agents for
work
> - Chat endpoints publish agent replies to providers such as GitHub,
and a durable outbox classifies each send failure
> - A GitHub review run that fails posts a "review failed" reply. When
the run has no request binding, Paperclip throws its own `forbidden()`
before any GitHub request
> - The classifier reads that local 403 as a provider credential
failure. The endpoint goes to `attention`, its tool connection is
disabled, and new `pull_request` webhooks are dropped
> - One failed review can stop all reviews on that endpoint until an
operator reconnects it
> - This pull request classifies Paperclip's own 401/403 `HttpError`
without a provider status as a failure of that publication only
> - The benefit is that only real provider credential failures lock an
endpoint

## Linked Issues or Issue Description

Fixes: #16137

## What Changed

- `server/src/services/chat-publication-errors.ts`: an `HttpError`
(Paperclip's own class) with status 401 or 403 and no numeric
`details.providerStatus` returns `{ kind: "failed" }`. The check runs
before the credential branch.
- Provider errors do not change. Adapter
`AuthenticationError`/`PermissionError`, Octokit errors (named
`HttpError`, but not this class) and Paperclip-wrapped provider
rejections that carry `providerStatus` still return
`endpoint_attention`.
- `server/src/services/chat-publication-errors.test.ts`: a new test
covers a local `forbidden()`, a local `unauthorized()` and a wrapped
provider 403.

## Verification

- `pnpm --filter @paperclipai/server vitest run
src/services/chat-publication-errors.test.ts`
- I ran the classifier source with type stripping on Node 22: local
`forbidden("GitHub failure has no request binding")` → `failed`; local
`unauthorized()` → `failed`; `new HttpError(403, …, { providerStatus:
403 })` → `endpoint_attention`; an Octokit-shaped 403 →
`endpoint_attention`.
- I applied the same change to the built `dist` of a self-hosted install
and called its classifier with the same four errors. The results were
the same.

## Risks

- Low risk. The change applies only to Paperclip's own `HttpError` with
status 401/403 and no provider status. Such an error now fails one
publication and does not disable the endpoint. Code that throws a local
401/403 to report a provider credential problem must attach
`providerStatus`. I found no such caller in `server/src/services`.

## Model Used

- Claude Opus 5.5 (`claude-opus-5-5`, Anthropic), in Claude Code with
tool use (shell, file edits, test runs). It helped to find the cause,
write the change and the test, and run the checks.

## Checklist

- [x] I have included a thinking path that traces from project context
to this change
- [x] I have specified the model used (with version and capability
details)
- [x] I have checked ROADMAP.md and confirmed this PR does not duplicate
planned core work
- [x] I have searched GitHub for duplicate or related PRs and linked
them above
- [x] I have either (a) linked existing issues with `Fixes: #` / `Closes
#` / `Refs #` OR (b) described the issue in-PR following the relevant
issue template
- [x] I have not referenced internal/instance-local Paperclip issues or
links (only public GitHub `#NNN` / `github.com/paperclipai/paperclip`
URLs)
- [x] My branch name describes the change (e.g. `docs/...`, `fix/...`)
and contains no internal Paperclip ticket id or instance-derived details
- [ ] I have run tests locally and they pass (classifier checked with
type stripping; the full vitest suite runs in CI)
- [x] I have added or updated tests where applicable
- [x] I have updated relevant documentation to reflect my changes
- [x] I have considered and documented any risks above
- [ ] All Paperclip CI gates are green
- [ ] Greptile is 5/5 with no open P2s, recommendations, or follow-ups
- [x] I will address all Greptile and reviewer comments before
requesting merge

server/src/services/chat-publication-errors.test.ts

@@ -1,4 +1,5 @@
 import { describe, expect, it } from "vitest";
+import { forbidden, HttpError, unauthorized } from "../errors.js";
 import { classifyChatPublicationError } from "./chat-publication-errors.js";
 
 function providerError(
@@ -155,6 +156,27 @@ describe("chat publication error classification", () => {
     ).toMatchObject({ kind: "endpoint_attention" });
   });
 
+  it("keeps Paperclip's own authorization failures scoped to the publication", () => {
+    expect(
+      classifyChatPublicationError(
+        forbidden("GitHub failure has no request binding"),
+        1,
+      ),
+    ).toMatchObject({ kind: "failed" });
+    expect(classifyChatPublicationError(unauthorized(), 1)).toMatchObject({
+      kind: "failed",
+    });
+    expect(
+      classifyChatPublicationError(
+        new HttpError(403, "GitHub rejected this operation", {
+          code: "github_bot_operation_failed",
+          providerStatus: 403,
+        }),
+        1,
+      ),
+    ).toMatchObject({ kind: "endpoint_attention" });
+  });
+
   it("does not call explicit GitHub 4xx rejections ambiguous delivery", () => {
     for (const status of [400, 409, 422]) {
       expect(

server/src/services/chat-publication-errors.ts

@@ -1,3 +1,5 @@
+import { HttpError } from "../errors.js";
+
 export type ChatPublicationErrorDisposition =
   | {
       kind: "retry";
@@ -317,6 +319,15 @@ export function classifyChatPublicationError(
     return { kind: "resource_unavailable", reason };
   }
 
+  if (
+    error instanceof HttpError &&
+    (error.status === 401 || error.status === 403) &&
+    typeof (error.details as { providerStatus?: unknown } | undefined)
+      ?.providerStatus !== "number"
+  ) {
+    return { kind: "failed", reason };
+  }
+
   if (
     names.includes("AuthenticationError") ||
     names.includes("PermissionError") ||