fix(apiproxy): configure session export compression

Session-log ZIP entries always used DEFLATE level 6 even though compression level is a deployment tradeoff: CPU-constrained hosts may prefer low latency while bandwidth-constrained hosts may prefer smaller archives. A hardcoded level also violated the repository rule that deployment-varying plugin choices live in validated Config.

Add sessionExportCompressionLevel to ApiProxyService.Config as an integer 0-9 with default 6, resolve the same default once for direct createApiProxy callers, and pass the required level into the streaming module. Tests prove schema defaulting and rejection as well as a level-0 versus level-9 archive-size difference with identical extracted content. The generated config catalog, bilingual gateway README, and feature note document the knob and its tradeoff.

packages/host/apiproxy/src/index.ts

@@ -17,6 +17,10 @@ import z from '@deepseek-ai/schemastery'
 import type {} from '@deepseek-ai/dsh-agent-default-model'
 import type { ApiProxy } from './api/index.ts'
 import { createApiProxy } from './api-proxy.ts'
+import {
+  DEFAULT_SESSION_LOG_COMPRESSION_LEVEL,
+  type SessionLogCompressionLevel,
+} from './session-export.ts'
 
 export type * from './api/index.ts'
 export { RpcId } from './api/rpc.ts'
@@ -33,7 +37,7 @@ declare module '@deepseek-ai/cordis' {
   }
 }
 
-/** Gateway plugin config for native Host integration. */
+/** Gateway plugin configuration. */
 export interface Config {
   /**
    * Whether this deployment can hand paths to a native desktop opener —
@@ -43,6 +47,12 @@ export interface Config {
    * container whose DISPLAY points nowhere a user can see.
    */
   nativeOpen?: boolean
+  /**
+   * DEFLATE level for every session-log ZIP entry: `0` stores without
+   * compression, `1` favors CPU/latency, and `9` favors archive size.
+   * @default 6
+   */
+  sessionExportCompressionLevel?: 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9
 }
 
 /**
@@ -58,6 +68,8 @@ export class ApiProxyService extends Service implements ApiProxy {
 
   static Config: z<Config> = z.object({
     nativeOpen: z.boolean(),
+    sessionExportCompressionLevel: z.number().step(1).min(0).max(9)
+      .default(DEFAULT_SESSION_LOG_COMPRESSION_LEVEL) as z<SessionLogCompressionLevel>,
   })
 
   readonly sessions: ApiProxy['sessions']
@@ -82,6 +94,7 @@ export class ApiProxyService extends Service implements ApiProxy {
       saveDefaultModelSelection: selection => ctx.agentDefaultModel.saveSelection(selection),
       cwd: process.cwd(),
       ...config.nativeOpen === undefined ? {} : { canOpenPath: () => config.nativeOpen as boolean },
+      sessionExportCompressionLevel: config.sessionExportCompressionLevel ?? DEFAULT_SESSION_LOG_COMPRESSION_LEVEL,
     })
     this.sessions = api.sessions
     this.subagents = api.subagents