revert(egress-proxy): drop Role + agent provisioner (keep git-push block)

Partial revert of fa06a3a. The role + agent-side provisioner felt
overengineered: anthropic-base-url + npm-registry's only realistic
host values match the tool defaults, so the role tags drove no-op
dotfile writes most of the time. If non-default npm registry / tea
config is needed in a future bottle, we can ship it through a more
direct mechanism then.

What stays from fa06a3a:
  - Universal HTTPS git-push block in the egress-proxy addon
    (`is_git_push_request` in egress_proxy_addon_core, called from
    the request hook before route matching; 403s git-receive-pack
    regardless of route). This is the security backstop so git-gate
    remains the only outbound write path; PR #29 keeps it.

What gets reverted:
  - `Role` field on EgressProxyRoute (manifest + runtime).
  - `EGRESS_PROXY_ROLES` + `EGRESS_PROXY_SINGLETON_ROLES` constants
    and singleton-role validation.
  - `backend/docker/provision/egress_proxy.py` (npmrc + tea config).
  - `provision_egress_proxy` slot in `BottleBackend.provision`.
  - `prepare.py`'s role-based ANTHROPIC_BASE_URL detection (back to
    the token_ref="CLAUDE_CODE_OAUTH_TOKEN" auto-detect).
  - Manifest + provisioner tests for the above.

355 unit + 24 integration tests pass.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

claude_bottle/egress_proxy.py

@@ -62,19 +62,13 @@ class EgressProxyRoute:
     (e.g. `EGRESS_PROXY_TOKEN_0`); `token_ref` is the host env var
     the CLI reads at launch and forwards into the container's environ
     under `token_env`. Routes that share a `token_ref` coalesce to
-    one `token_env` slot.
-
-    `roles` are the provisioner tags from the manifest route (see
-    `manifest.EGRESS_PROXY_ROLES`). Each tag drives one agent-side
-    dotfile / env rewrite at bottle bring-up. The addon never reads
-    these — they flow through the plan to the host-side provisioner."""
+    one `token_env` slot."""
 
     host: str
     path_allowlist: tuple[str, ...] = ()
     auth_scheme: str = ""
     token_env: str = ""
     token_ref: str = ""
-    roles: tuple[str, ...] = ()
 
 
 @dataclass(frozen=True)
@@ -154,13 +148,11 @@ def egress_proxy_routes_for_bottle(
                 auth_scheme=r.AuthScheme,
                 token_env=token_env,
                 token_ref=r.TokenRef,
-                roles=r.Role,
             ))
         else:
             out.append(EgressProxyRoute(
                 host=r.Host,
                 path_allowlist=r.PathAllowlist,
-                roles=r.Role,
             ))
     return tuple(out)