feat(config)!: one ordering for configuration sources, and a bootstrap deny rule

$DSH_HOME/.env had just become an ordinary environment layer, which left the
harness resolving user-facing values from a flattened process.env that could
no longer say where a value came from. A key stored through the web page
stayed shadowed by an older key in the user's own .env. An endpoint could be
redirected by the project: the invoking directory's .env is materialized like
every other layer, and a base URL decides where a resolved API key is sent, so
a DEEPSEEK_BASE_URL written into a model-editable workspace would send the
user's credential — and the prompts carrying their code — to whatever host
that file named.

Give every user-facing value one ordering, with four kinds of source:

  explicit for this run     per-operation override, CLI argument
  > authored by deployment  --config / --config-replace
  > this launch's shell     inherited process environment
  > product-managed store   settings.yaml, .credentials.yaml
  > discovered file         $DSH_HOME/.env
  > defaults                schema default, shipped base, public default

The domains differ only in which tiers exist. The earlier split — credentials
ranking the environment over the managed file while settings ranked over the
environment — was inconsistent: the distinguishing fact is who authored the
source, not the domain.

packages/util/environment owns an immutable snapshot with per-layer
provenance. getFrom(name, sources) searches only the layers a caller names,
and omitting one is a refusal rather than a demotion: the adapters ask for
['process', 'user-env'], so no reordering can let a project file back into a
decision it was excluded from.

isBootstrapOnly rejects, before anything is materialized, any .env setting a
variable that governs how a process launches (PATH, SHELL, NODE_OPTIONS,
LD_PRELOAD), where code or model-visible instructions load from (the whole
DSH_* namespace, HOME, XDG_*), or how the network is reached (proxy and CA
variables). The namespace is denied wholesale so a switch added later cannot
become settable by being forgotten, and there is no opt-out.

verify-config-source-ownership keeps both rules: no unregistered process.env
read under packages/*/*/src (26 allowlisted with reasons), and no apiKey,
baseURL, or headers inlined from the environment in shipped Cordis config —
removing those inlines is what makes the deployment tier meaningful.

apps/cli/src/headless.ts

@@ -10,6 +10,7 @@
 
 import { fileURLToPath } from 'node:url'
 import { resolveConfigPath } from '@deepseek-ai/dsh-app-boot'
+import type { EnvironmentSnapshot } from '@deepseek-ai/dsh-environment'
 import { InProcessApiClient, toFetchHandler } from '@deepseek-ai/dsh-host-apiproxy'
 import type { MuxFrame } from '@deepseek-ai/dsh-host-apiproxy/api'
 import type { RpcRequest, RpcResponse } from '@deepseek-ai/dsh-host-apiproxy/api/rpc'
@@ -71,15 +72,19 @@ async function consumeUntilTurnEnd(frames: AsyncIterable<RpcRequest<MuxFrame>>,
  * Run one headless turn for `task` and exit (completed → 0, else 1). The task
  * is the non-empty prompt the argument adapter parsed from `-p`/`--prompt`
  * (the adapter rejects an empty task, so no guard is needed here).
+ * @param environment - this run's frozen environment snapshot.
  * @param task - the prompt text for the single turn.
  * @param config - a `--config` overlay applied over the shipped composition, or `undefined`.
  * @param configReplace - a `--config-replace` tree booted instead of the
  * shipped composition, or `undefined`. It must mount a webserver row: this
  * surface reaches its own agent over the same HTTP gateway the browser uses.
  */
-export async function runHeadless(task: string, config?: string, configReplace?: string): Promise<void> {
+export async function runHeadless(
+  environment: EnvironmentSnapshot, task: string, config?: string, configReplace?: string,
+): Promise<void> {
   // A missing DEEPSEEK_API_KEY throws here (plugin load is fail-loud, uncaught by design).
   const entry = new AppCLIEntry({
+    environment,
     configPath: fileURLToPath(new URL('../config/base.cordis.yml', import.meta.url)),
     overlayPath: fileURLToPath(new URL('../config/web.cordis.yml', import.meta.url)),
     ...config !== undefined && { extraOverlayPath: resolveConfigPath(config, undefined) },