fix: address Copilot review (9 comments)

#1 GitView: hide/disable 'open in editor' for external linked worktrees
   (path outside session workspace is rejected by the fence); add
   isWithinWorkspace client helper for the gate.
#2 DiffTab: untracked diff read resolves against diff.repoRoot (child-repo
   paths are repo-root-relative, not cwd-relative); fs.read route threads
   selectedRepoOf into resolveGitPath so the host resolves the right base.
#3 GitView: chooseRepo handler mirrors chooseWorktree — clears status/
   history/log and bumps generation before async refresh, preventing stale
   rows from acting on the newly selected repository.
#4 git.ts: repoRoots/repoRoot compare roots via pathIdentity() (platform-
   aware) instead of raw includes(), fixing win32 forward/backslash
   mismatch that silently fell back to roots[0].
#5 markdown-images: mask fenced code blocks and inline code spans before
   rewriting; only rewrite reference definitions whose label is actually
   referenced by image syntax (not plain links). +3 tests.
#6 package.json: downgrade unrun ^0.3.1 → ^0.2.39 (0.3.x requires Node
   ^22.13, incompatible with declared engines >=20).
#7 market-manifest.spec: shell:true on win32 so execFileSync resolves the
   pnpm .cmd shim.
#8 smoke.spec: build html-route URL via encodeHtmlUrl() (production
   encoder) so the Windows drive separator is correct.
#9 index.ts git.worktrees route: thread selectedRepoOf so a workspace
   container's selected child repo's linked worktrees appear.

tests/smoke.spec.ts

@@ -12,6 +12,7 @@ import { SettingsConflictError, settingsNamespace } from '@deepseek-ai/dsh-setti
 import { apply, mediaTypeForPath } from '../src/index.ts'
 import * as git from '../src/git.ts'
 import { listDirectory } from '../src/fs-tree.ts'
+import { encodeHtmlUrl } from '../src/html-route.ts'
 import { defaultShell, PtyManager, type SidebarPty } from '../src/pty-manager.ts'
 import type { SidebarWebRoute, SidebarWebUpgradeRoute } from '../src/context-types.ts'
 
@@ -636,8 +637,10 @@ describe('session cwd resolution over the API route', () => {
       const media = routes.find(route => route.path === '/sidebar/file')!
       const html = routes.find(route => route.path === '/sidebar/html')!
       const mediaResult = await invokeGet(media, `/sidebar/file?sessionId=security&path=${encodeURIComponent(join(workspace, 'link', 'secret.png'))}`)
-      const htmlPathname = join(workspace, 'link', 'secret.html').replace(/\\/g, '/').split('/').map(encodeURIComponent).join('/')
-      const htmlResult = await invokeGet(html, `/sidebar/html/security${htmlPathname}`)
+      // Use the production encoder so the URL is well-formed on every
+      // platform (a Windows drive path needs the leading slash separator
+      // that a naive join-without-separator drops).
+      const htmlResult = await invokeGet(html, encodeHtmlUrl('security', join(workspace, 'link', 'secret.html')))
       expect(mediaResult).toMatchObject({ status: 403 })
       expect(JSON.parse(mediaResult.body)).toMatchObject({ ok: false, error: { code: 'forbidden' } })
       expect(htmlResult).toMatchObject({ status: 403 })