docs: correct stale role field and claude provider auth example

The egress route fields table described `role` as a functional field
that wires built-in auth flows. PRD 0029 removed the
`claude_code_oauth` role; the manifest parser now rejects any `role`
value as reserved-for-future-use. Provider auth routes are injected
from `agent_provider.auth_token`.

- README: fix the `role` row to state it is reserved and any value is
  rejected at load.
- examples/bottles/claude.md: the manual `api.anthropic.com` route used
  the rejected `role` key and, even without it, would be silently
  dropped (provider-injected routes win for a provisioned host) — so its
  auth never took effect and the dlp comments described a route that
  never exists in the plan. Replace it with the canonical
  `agent_provider.auth_token` shape.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01YcU7nerbg8cVj9R4EkpfLJ

examples/bottles/claude.md

@@ -1,19 +1,14 @@
 ---
 agent_provider:
   template: claude
-
-egress:
-  routes:
-    - host: api.anthropic.com
-      role: claude_code_oauth    # wires Claude Code OAuth; do not change
-      auth:
-        scheme: Bearer
-        token_ref: BOT_BOTTLE_CLAUDE_OAUTH_TOKEN
-      # dlp is omitted → all detectors on by default (token_patterns,
-      # known_secrets outbound; naive_injection_detection inbound).
-      # To disable inbound scanning for this route:
-      #   dlp:
-      #     inbound_detectors: false
+  # auth_token names the host env var holding the Claude OAuth token. The
+  # provider injects a provider-owned api.anthropic.com egress route that
+  # re-injects this token as the Bearer header; the agent only ever sees a
+  # placeholder CLAUDE_CODE_OAUTH_TOKEN. DLP defaults (token_patterns,
+  # known_secrets outbound; naive_injection_detection inbound) apply to
+  # that route. To scan additional hosts, declare them under egress.routes
+  # with per-route matches/dlp (see README "Egress route fields").
+  auth_token: BOT_BOTTLE_CLAUDE_OAUTH_TOKEN
 ---
 
 Common Claude provider boundary. Drop this file into