fix: container mount permissions, terminal shift, ESC capture

Bug 1 — in-container repo mounting:
- docker-compose.yml: added /data/working-copies:/data/working-copies mount
  to API container so workspace dirs are visible on host filesystem
- Dockerfile: create /data/working-copies dir in image

Bug 2 — /home/user not writable:
- workspace_manager.py: chmod 777 workspace dirs + 666 files after clone
  and after sync, so any container user can write
- manifest_compiler.py: explicit mkdir + chown + chmod 755 for home dir
  in generated Dockerfile

Bug 3 — terminal text shifts left on typing:
- terminal.tsx: removed manual term.refresh() after fit (caused reflow)
- Track lastSentCols/lastSentRows and only send resize when dimensions
  actually changed, preventing resize feedback loops

Bug 4 — ESC key captured by terminal:
- terminal.tsx: attachCustomKeyEventHandler allows ESC to propagate to
  browser when not in alternate buffer (vim/tmux), so modals/navigation
  work; ESC still sent to PTY when in vim/tmux alternate screen

Quality gates: ruff clean, tsc --noEmit clean, pytest workspaces (9 passed)

apps/api/Dockerfile

@@ -50,8 +50,8 @@ ENV PATH=/root/.local/bin:$PATH
 # Copy application code
 COPY --chown=appuser:appgroup . .
 
-# Create directories for repo and instance storage
-RUN mkdir -p /data/repos /data/instances && chown -R appuser:appgroup /data
+# Create directories for repo, instance, and workspace storage
+RUN mkdir -p /data/repos /data/instances /data/working-copies && chown -R appuser:appgroup /data
 
 # Copy wait-for-db script
 COPY wait-for-db.sh /usr/local/bin/wait-for-db.sh