Merge remote-tracking branch 'origin/master' into worktree/default-model-persistence

Carries two edits beyond conflict resolution, both forced by what master
brought in:

- `CustomProviderCard`: master added front-end key validation and a
  component-level `keyValue` (already trimmed) while still writing
  `apiKeyEnv` unconditionally. Kept this branch's blank-key rule and its
  committed-profile retry gate, and adopted master's single `keyValue` so
  the component has one spelling of the key rather than two.
- `docs/user/guide/providers`: master merged #1810, whose default-model
  section still taught overriding the `api-gateway` row in
  `$DSH_HOME/config.yaml` — the behavior this branch replaced. Rewritten
  for the settings section the picker now writes, plus the review fix from
  #1810 replacing the colloquial 挂着 in the opener.

packages/host/apiproxy/src/native-path-opener.ts

@@ -1,5 +1,6 @@
 /** Cross-platform native path and text-document openers used by the local GUI carrier. */
 
+import { release as osRelease } from 'node:os'
 import { runNativeCommand, type NativeCommandRunner } from '@deepseek-ai/dsh-native-command'
 
 /** Testable command boundary; native implementations never invoke a shell. */
@@ -8,6 +9,10 @@ export type PathOpenerRunner = NativeCommandRunner
 /** Injectable platform facts for deterministic adapter tests. */
 export interface PathOpenerInternals {
   platform?: NodeJS.Platform
+  /** Kernel release override used to distinguish WSL from desktop Linux. */
+  osRelease?: string
+  /** WSL environment marker override used with the kernel release. */
+  env?: Readonly<Partial<Record<'WSL_DISTRO_NAME' | 'WSL_INTEROP', string>>>
   run?: PathOpenerRunner
 }
 
@@ -19,6 +24,36 @@ function powershellLiteral(path: string): string {
   return `'${path.replace(/'/g, "''")}'`
 }
 
+/** Whether one environment marker is set to a non-empty value. */
+function present(value: string | undefined): boolean {
+  return value !== undefined && value !== ''
+}
+
+/** Distinguish WSL from desktop Linux using its process and kernel markers. */
+function isWsl(internals: PathOpenerInternals): boolean {
+  const env = internals.env ?? process.env
+  if (present(env.WSL_DISTRO_NAME) || present(env.WSL_INTEROP)) return true
+  return (internals.osRelease ?? osRelease()).toLowerCase().includes('microsoft')
+}
+
+/** Open one Windows-resolvable path through its registered desktop application. */
+async function openWindowsPath(path: string, signal: AbortSignal, run: PathOpenerRunner): Promise<void> {
+  await run('powershell.exe', [
+    '-NoProfile',
+    '-Command',
+    `Invoke-Item -LiteralPath ${powershellLiteral(path)}`,
+  ], signal)
+}
+
+/** Translate a WSL path before handing it to the Windows desktop. */
+async function openWslPath(path: string, signal: AbortSignal, run: PathOpenerRunner): Promise<void> {
+  const translated = await run('wslpath', ['-w', path], signal)
+  signal.throwIfAborted()
+  const windowsPath = translated.stdout.replace(/[\r\n]+$/, '')
+  if (windowsPath === '') throw new Error('wslpath returned no Windows path')
+  await openWindowsPath(windowsPath, signal, run)
+}
+
 /** Dispatch one shell-free platform command for the requested open intent. */
 async function openNativePathWithIntent(
   path: string,
@@ -35,15 +70,15 @@ async function openNativePathWithIntent(
   }
 
   if (platform === 'win32') {
-    await run('powershell.exe', [
-      '-NoProfile',
-      '-Command',
-      `Invoke-Item -LiteralPath ${powershellLiteral(path)}`,
-    ], signal)
+    await openWindowsPath(path, signal, run)
     return
   }
 
   if (platform === 'linux') {
+    if (isWsl(internals)) {
+      await openWslPath(path, signal, run)
+      return
+    }
     await run('xdg-open', [path], signal)
     return
   }