runtime contexts (ctx.systemPrompt.context) never reach the model — dsh 0.1.5-rc.1

🇨🇳 TL;DR：`ctx.systemPrompt.context()` 注册的 `user-settings` / `memory` 两个块从未送达模型。`/api/dsh-mneme/features` 显示 `autoInject: true`，`/api/dsh-mneme/profile` 返回正确文本，但新会话里模型完全不知道画像内容；会话日志里也搜不到任何 runtime-context 快照。

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## Environment

| | |
|---|---|
| dsh | `0.1.5-rc.1` |
| `@modusensus/dsh-mneme` | `0.8.0` |
| `@deepseek-ai/dsh-system-prompt` | `0.1.5-rc.2` |
| Node | `v22.22.3` |
| OS | Windows 11 (10.0.26200) |
| profile | `web` |

## Expected

The `[用户设置] 来自 dsh-mneme 的用户画像与规则：` block (profile + rules) should be injected at session start (and per the README, every turn), so the model knows the user profile.

## Actual

The model never receives it. In a fresh session, asking the agent "我的用户画像里写了什么？" returns nothing.

## Plugin side looks correct

1. `src/inject.js` registers both contexts:
- `ctx.systemPrompt.context({ name: "user-settings", order: 85, text: renderUserSettings })`
- `ctx.systemPrompt.context({ name: "memory", order: 90, text: (ctx) => ... })`
2. Gate is open — `GET /api/dsh-mneme/features` returns `"effective": { "autoInject": true, ... }`
3. Data is readable — `GET /api/dsh-mneme/profile` returns the configured profile text (redacted)
4. `settings.getProfile()` reads `user_settings.profile` (`src/settings.js:275`)
5. `@deepseek-ai/dsh-system-prompt` is present and enabled, with **no** `includeRuntimeContext` override (i.e. default `true`)
6. **No installed plugin calls `suppressRuntimeContext()`** (grepped all profile `node_modules`)

## Session-history evidence

Decompressed `$DSH_HOME/sessions//session-/session.v3.jsonl.zstd` — **431 concatenated zstd frames → 5.29 MB JSONL**.

> Note for anyone reproducing: the Node APIs `zstdDecompressSync` / `createZstdDecompress` only decode the **first** frame here, so the file has to be decompressed frame-by-frame via the `28 B5 2F FD` magic.

Searched for:

| needle | result |
|---|---|
| `Current runtime context. This snapshot supersedes earlier runtime-context snapshots.` | only in my own debug output, earliest at **95%** of the file |
| `[用户设置] 来自 dsh-mneme` | same |
| `- 用户画像：` (`lang.js` `profileLine` template) | 105 hits, **all after 97.3%**, all my own text |

So the runtime-context snapshot never materialized into session history.

## Caveat

I could not confirm whether DSH is supposed to persist runtime contexts into session history at all (it may be assembled per-request only). If it is not persisted, the session-log evidence is weak — in that case the primary symptom is the model-side one above.

## Working workaround

Re-enabling the built-in `agent-instructions` plugin (the `dsh-web-app` bundle ships it as `disabled: true`) and putting the profile/rules into `$DSH_HOME/AGENTS.md` **does** reach the model. So the problem looks specific to the `systemPrompt.context()` path on this DSH build.

## Question

Is this a plugin-side registration-shape issue for this DSH version, or a DSH-side change in how runtime contexts get materialized? Happy to run further diagnostics.