fix(config): close the review findings on configuration source ownership

Two had real security consequences:

The bootstrap rejection ran on npm dotenv's parser while process.loadEnvFile
applied the file with Node's own. Two independently maintained dialects meant
the check and the thing it guards could disagree: a name Node accepts but the
checker misses would reach process.env unchecked, and BASH_ENV there runs a
file of the project's choosing on every `bash -c` the bash tool issues. Parse
once with node:util's parseEnv — the same engine loadEnvFile uses — and assign
the entries already checked, which also drops the dotenv dependency.

llm-pi-ai still returned a literal profile.apiKey ahead of everything, and it
registers a settings namespace, so the defect removed from llm-deepseek
survived intact in its design twin. The field is gone from the profile schema,
the resolution path, and the tests.

The rest are consistency and documentation defects the review named:

- verify-config-source-ownership did not scan the Python runtime's bundled
  cordis.yml, which still inlined apiKey and baseURL. Both are covered now, and
  the line-anchored INLINE_DENY documents that it is a tripwire, not a parser.
- The deny list missed NODE_TLS_REJECT_UNAUTHORIZED, the askpass hooks, the
  GIT_CONFIG_* redirections, and PYTHONHOME — all implied by its own stated
  rule about what a variable does.
- Snapshot lookups folded case on Windows, where environment names are
  case-insensitive and an exact-match Map could miss a higher-ranked layer.
- The credentials note claimed a read-time permission check was "not taken"
  while this PR implemented it; the credentials-local README still described
  two layers, live process.env reads, dotenv-era limitations, and a renamed
  anchor; the llm-deepseek README still advertised the removed literal apiKey;
  and web.ts and base.cordis.yml kept personal-overlay wording.
- The ownership note's literal-apiKey claim now names its scope: the
  web-search providers keep a literal field but register no settings
  namespace, so nothing can shadow a stored credential through them.

.agents/notes/implemented/architecture/2026-08-04-configuration-source-ownership.zh.md

@@ -58,7 +58,7 @@ inherited process environment      (read-only, wins)
 - 含 `DSH_*`、`PATH` 或 proxy 变量的 `.env` 会导致启动失败而不是被应用。把开关放在仓库 `.env` 里的开发者需要改放到 shell——这是一次刻意且响亮的破坏。
 - `--config` 不再会被陈旧的 shell endpoint 覆盖。但它仍然会被用户已存的 `settings.yaml` 覆盖，这是 settings seam 的分层方式，本 Note 不改变它；需要压过已存 settings 的部署方应使用 `--config-replace`。
 - 未解决的：各层仍然会被物化进 `process.env`，因此普通项目变量继续按子进程清洗规则抵达子进程。bootstrap 变量完全不能来自文件，提权路径已封闭；项目 `.env` 为 agent 运行的工具设置诸如 `GIT_SSH_COMMAND` 之类的变量仍然可能，已作为限制记录在该包上。
-- 适配器不再接受字面 `apiKey`：配置只携带引用，因此 settings 文档无法成为第二个凭据存储。由于没有任何适配器 namespace 是 strict 的，写入该键会被 schema 丢弃而不是报错。
+- LLM 适配器不再接受字面 `apiKey`：配置只携带引用，因此 settings 文档无法成为第二个凭据存储。由于没有任何适配器 namespace 是 strict 的，写入该键会被 schema 丢弃而不是报错。web-search 提供方仍声明 `role('secret')` 的字面密钥字段；它们不注册 settings namespace，因此无法借此遮蔽已存凭据，但这条声明的范围是适配器，而不是整个仓库。
 - Exa 与 Perplexity 仍在加载时捕获密钥，而不是经凭据 seam。它们不再读裸 `process.env`——改为经受信层解析——但把它们改造成按请求经 seam 解析是另一件事。
 
 ## Alternatives considered