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.

src/index.ts

@@ -286,8 +286,11 @@ function buildApi(
     'fs.read': async (payload) => {
       const { cwd } = cwdOf(payload)
       // Relative paths are git-derived (status/diff report repo-root-relative
-      // names; the untracked diff view reads the file through this route).
-      const path = await ensureWorkspacePath(cwd, await resolveGitPath(cwd, requireString(payload, 'path')))
+      // names; the untracked diff view reads the file through this route). A
+      // child-repo path is relative to the selected repoRoot, not the session
+      // cwd; thread it so the path resolves inside the authorized workspace.
+      const selected = selectedRepoOf(payload)
+      const path = await ensureWorkspacePath(cwd, await resolveGitPath(cwd, requireString(payload, 'path'), selected))
       const { content, truncated, binary, size, head } = await readText(path, resolved.readLimit)
       if (binary) return { kind: 'binary', size, truncated, head }
       return { kind: 'text', content, truncated }
@@ -308,8 +311,13 @@ function buildApi(
       return { ok: true }
     },
     'git.worktrees': async (payload) => {
-      const { cwd } = cwdOf(payload)
-      return git.worktrees(cwd)
+      const { cwd } = await gitCwdOf(payload)
+      const selected = selectedRepoOf(payload)
+      // A workspace container (no repo at cwd) has child repos; the worktree
+      // list belongs to the SELECTED child, not the container. Thread the
+      // validated repoRoot so linked checkouts of a chosen child appear.
+      const base = selected !== undefined ? await git.repoRoot(cwd, selected).catch(() => cwd) : cwd
+      return git.worktrees(base)
     },
     'git.status': async (payload) => {
       const { cwd } = await gitCwdOf(payload)