fix: wrap message-part-directory with LRE/PDF for RTL path display

[tamish560]

What

Fixes the 3 remaining message-part-directory spans in message-part.tsx that were not covered by PR #9591.

Problem

CSS direction: rtl on [data-slot="message-part-directory"] (used for left-side ellipsis) causes the Unicode bidi algorithm to reposition leading dots in path names like .config/opencode/, rendering as config/opencode./.

PR #9591 fixed this in session-review.tsx and session-turn.tsx by wrapping the directory text with ‪...‬ (LRE + PDF unicode marks). The same issue exists in 3 places in message-part.tsx that were missed.

Fix

Wrapped the 3 remaining message-part-directory spans with the same ‪${getDirectory(...)}‬ pattern:

1. message-part-directory with getDirectory(props.input.filePath!) (2 instances)
2. message-part-directory with getDirectory(single()!.relativePath) (1 instance)

The apply-patch-directory spans in the same file already had this fix applied.

Closes #36489

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[github-actions]

The following comment was made by an LLM, it may be inaccurate:

Potential Duplicate Found

PR #36488: fix(session-ui): escape direction:rtl bidi issue in message-part-directory via LRE/PDF wraps
#36488

Why it's related: This PR appears to address the same RTL bidi issue with message-part-directory using the same LRE/PDF unicode wrapping solution. Since the current PR (36508) mentions fixing "3 remaining" instances that were missed in PR #9591, PR #36488 may be an alternative or overlapping fix for the same problem.

[tamish560]

Closing this as #36488 by @windlandneko was opened first and covers the same fix (LRE/PDF wrapping in message-part.tsx for the same issue #36489). Didn't realize there was already a PR for this when I opened mine. Will watch for duplicates next time.