Add worktrees, per-hunk review, effort per message, regenerate, voice input

- Isolated git worktree per session (create, status, merge, discard)
- Permission card: accept file-edit hunks individually; agent learns what was rejected
- Reasoning effort per message; regenerate the last answer with another model/effort
- Voice input via the Web Speech API
- Folder-up button in the file browser; ssh, rsync and mc in the image

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

Dockerfile

@@ -29,6 +29,7 @@ RUN apt-get update && apt-get install -y --no-install-recommends \
         build-essential pkg-config libssl-dev cmake zlib1g-dev binutils-multiarch \
         chromium fonts-dejavu-core fonts-noto-color-emoji poppler-utils openmpt123 \
         openscad xvfb xauth \
+        openssh-client rsync mc \
     && rm -rf /var/lib/apt/lists/*
 # Language servers for diagnostics after edits (rust-analyzer/gopls/clangd can be
 # installed by agents: rustup component add rust-analyzer, go install …).