refactor(cred_proxy): flat routes, role-driven provisioning (PRD 0010)

Replace bottle.tokens (with Kind enum and hardcoded per-kind
route/auth tables) with bottle.cred_proxy.routes — each route
declares its own path, upstream, auth_scheme, token_ref, and
optional role[]. The manifest is now the source of truth for the
proxy's runtime route table; adding an upstream is a manifest edit,
not a code change.

Agent-side rewrites move from per-kind dispatch to per-role tags
on routes:
  anthropic-base-url -> set ANTHROPIC_BASE_URL=<proxy><path>
  npm-registry       -> write ~/.npmrc registry=
  git-insteadof      -> write ~/.gitconfig [url] insteadOf, keyed
                        off route.upstream (suppressed when
                        bottle.git brokers the same host)
  tea-login          -> add a ~/.config/tea/config.yml login

Roles are a list (string accepted as sugar). A gitea route
typically carries ["git-insteadof", "tea-login"]. Singleton roles
(anthropic-base-url, npm-registry) appear on at most one route.

token_env slots are assigned per distinct TokenRef in declaration
order — two routes sharing a token_ref (e.g. github API + git
endpoints) share a slot.

Drops: TOKEN_KINDS, _KIND_ROUTES, _KIND_AUTH_SCHEME, _TOKEN_DEFAULT_HOST,
cred_proxy_route_path_for_gitea, the kind field on CredProxyUpstream,
and the kind-based hardcoding in pipelock_token_hosts (now derives
from route.UpstreamHost).

Legacy bottle.tokens manifests now die with a hint pointing at
bottle.cred_proxy.routes + this PRD. Tests rewritten end-to-end.
Docs + example.json + the dev ~/claude-bottle.json updated to match.

claude-bottle.example.json

@@ -43,13 +43,37 @@
         "GIT_AUTHOR_NAME": "Eric Diderich",
         "NODE_ENV":        "development"
       },
-      "tokens": [
-        { "Kind": "anthropic", "TokenRef": "CLAUDE_BOTTLE_OAUTH_TOKEN" },
-        { "Kind": "github",    "TokenRef": "GH_PAT" },
-        { "Kind": "gitea",     "TokenRef": "GITEA_TOKEN",
-          "Url":  "https://gitea.dideric.is" },
-        { "Kind": "npm",       "TokenRef": "NPM_TOKEN" }
-      ]
+      "cred_proxy": {
+        "routes": [
+          { "path":        "/anthropic/",
+            "upstream":    "https://api.anthropic.com",
+            "auth_scheme": "Bearer",
+            "token_ref":   "CLAUDE_BOTTLE_OAUTH_TOKEN",
+            "role":        "anthropic-base-url" },
+
+          { "path":        "/gh-api/",
+            "upstream":    "https://api.github.com",
+            "auth_scheme": "Bearer",
+            "token_ref":   "GH_PAT" },
+          { "path":        "/gh-git/",
+            "upstream":    "https://github.com",
+            "auth_scheme": "Bearer",
+            "token_ref":   "GH_PAT",
+            "role":        "git-insteadof" },
+
+          { "path":        "/gitea/dideric/",
+            "upstream":    "https://gitea.dideric.is",
+            "auth_scheme": "token",
+            "token_ref":   "GITEA_TOKEN",
+            "role":        ["git-insteadof", "tea-login"] },
+
+          { "path":        "/npm/",
+            "upstream":    "https://registry.npmjs.org",
+            "auth_scheme": "Bearer",
+            "token_ref":   "NPM_TOKEN",
+            "role":        "npm-registry" }
+        ]
+      }
     }
   },