render markdown preview in the file browser

docs/operations.md

@@ -344,7 +344,7 @@ The Changes view lists the files with their counts, opens a file's diff on click
 
 The Files tab browses the selected task's worktree, read-only (`internal/server/files.go`). `GET /api/tasks/{taskId}/dir?path=` lists one directory, directories first and then by name, without entries named `.git`; `GET /api/tasks/{taskId}/file?path=` returns one regular file. Both take a slash-separated path relative to the worktree root and work only while the task is active (409 otherwise). Every path is opened through an `os.Root` on the worktree, so a path that leaves it, through `..`, an absolute path or a symlink at any depth, is a 400; a path with a `.git` component is also refused. A listing reports each entry as `dir`, `file` (with its size) or `other`, following symlinks that stay inside the worktree (`symlink` marks them); a symlink that leaves the worktree or points nowhere is `other` and can't be opened. Gitignored entries are listed with `ignored` set: one `git check-ignore --stdin` per listing (`git.Ignored`) over the entries' paths, taken from the directory's real path so a listing reached through an in-worktree symlink is checked where it really lives; untracked paths under an ignored directory count as ignored, tracked files never do. The view shows them dimmed with `ignored` beside them, and they open like anything else. A listing stops at `maxDirEntries` entries with `truncated` set. A file read sends at most `maxFileBytes`, cut back to a whole UTF-8 character, with `truncated` set when the file is longer; a file with a NUL byte or invalid UTF-8 in that part is `binary` and comes back with no text.
 
-The view shows a breadcrumb from `worktree` down to the current directory or file, the directory's entries (a `../` row to go up), or the file's text with line numbers and a note when only its start is shown. Where you are is kept per task in memory, so switching tasks or tabs returns to it, but a relaunch starts at the root. It refetches what it shows 1.5s after the selected task's last tool result or turn end, keeping the scroll position.
+The view shows a breadcrumb from `worktree` down to the current directory or file, the directory's entries (a `../` row to go up), or the file's text with line numbers and a note when only its start is shown. A file whose name ends in `.md` is rendered as Markdown with the transcript's renderer (`MarkdownView`) instead, with relative image paths taken from the file's own directory. Where you are is kept per task in memory, so switching tasks or tabs returns to it, but a relaunch starts at the root. It refetches what it shows 1.5s after the selected task's last tool result or turn end, keeping the scroll position.
 
 ## Terminals