OpenClaw Fork sideload: unified attachment message (55375c53de6)

Sideload build for Galaxy S23 Ultra / emulator testing.

• Package: ai.openclaw.app.debugfork
• Name: OpenClaw Fork
• Branch: android-voice-debugfork-unified-msg (55375c5)
• Includes ClawSweeper review fixes cherry-picked from upstream PR head 455a806
• Upstream PR (no debugfork identity): openclaw#174152

Changes in this build vs prior fork-unified-msg-4825033:

• photo restored from __openclaw.media base64/artifact
• media://inbound left to openclaw#169470
• transcript in Copy/Select/Share/Reply
• bare [Transcription] keeps original text
• only voice-note-.m4a names hidden
• 12-line/700-char rule and composer chip split out of PR scope