refactor(cred_proxy): rename Upstream -> Route, fix tea-login AttributeError

Three leftovers from the manifest refactor:

1. provision/cred_proxy.py:223 referenced u.kind == 'gitea' for the
   tea login count — kind was removed from the runtime class, so any
   bottle with a tea-login route raised AttributeError at provision
   time. Switch to `'tea-login' in r.roles`.

2. The runtime class CredProxyUpstream is renamed to CredProxyRoute
   (its data is a route on the proxy, not an "upstream"; the field
   route.upstream is the upstream URL). Module's own naming now
   aligns with manifest.CredProxyRoute and routes.json.

3. cred_proxy_upstreams_for_bottle -> cred_proxy_routes_for_bottle;
   CredProxyPlan.upstreams -> CredProxyPlan.routes; local
   `upstreams` collections become `routes`. Callers in
   backend.py, launch.py, prepare.py, bottle_plan.py,
   provision/cred_proxy.py, and tests updated.

Also strips lingering `bottle.tokens` references from docstrings
(pipelock.py, cred_proxy.py prepare(), manifest._parse_https_host,
test_pipelock_allowlist.py module doc) and removes dead helpers
from the integration test (the _bottle helper used a tokens field
that no longer parses).

tests/unit/test_pipelock_allowlist.py

@@ -1,7 +1,7 @@
 """Unit: pipelock_effective_allowlist — the union of baked-in defaults,
 bottle.egress.allowlist, and cred-proxy upstream hosts derived from
-bottle.tokens (PRD 0010). Git upstreams declared in bottle.git do not
-contribute here; they flow through the per-agent git-gate (PRD 0008)."""
+bottle.cred_proxy.routes (PRD 0010). Git upstreams declared in bottle.git
+do not contribute here; they flow through the per-agent git-gate (PRD 0008)."""
 
 import unittest