Refactor remote operations to use client-daemon protobuf connection instead of direct SSH

[proboscis]

Problem

Remote operations (send, capture, git operations) bypass the daemon and execute SSH commands directly from the CLI. This causes:

1. Shell escaping bugs — messages containing ?, *, !, [ etc. are interpreted as globs by the remote shell (zsh). See the recent shellQuote stopgap fix.
2. Duplicated logic — the daemon already handles local session operations, but the CLI reimplements equivalent logic for remote targets via SSH.
3. No unified error handling — SSH failures surface as raw exit codes rather than structured errors.
4. Architectural inconsistency — the daemon rejects requests when TargetHost is set instead of delegating, forcing the CLI to maintain a parallel SSH-based code path.

Current state

The daemon (proto_handler.go) hard-errors on remote targets:

• CaptureSession — rejects if TargetHost != ""
• SendMessage — rejects if TargetHost != ""
• Git operations (GetDiffStats, GetBranchState, GetDiff) — only work on local paths

The CLI (remote_control.go) fills the gap with 8 functions that SSH directly:

Function	Purpose
captureRemoteMultiplexerFromInfo	Capture tmux/zellij pane
captureRemoteOpenCodeFromInfo	Capture OpenCode session
sendRemoteMultiplexerFromInfo	Send to tmux/zellij
sendRemoteTmuxBracketedPaste	Bracketed paste via tmux
sendRemoteZellijBracketedPaste	Bracketed paste via zellij
sendRemoteOpenCodeFromInfo	Send to OpenCode
runSSHScriptOutput	Execute shell script over SSH
runSSHOutputArgs	Base SSH execution

Proposed solution

Phase 1: Daemon handles remote targets

• Remove the TargetHost rejection guards in proto_handler.go
• When TargetHost is set, the daemon delegates to the remote host (SSH or daemon-to-daemon)
• CLI always goes through the daemon — never calls SSH directly

Phase 2: Daemon-to-daemon communication (stretch)

• Remote host's daemon handles the operation locally
• Eliminates SSH shell interpretation entirely — messages are passed as protobuf fields
• Client → local daemon → remote daemon → local tmux call

Phase 3: Enforce via semgrep

• Add a semgrep rule that forbids direct exec.Command("ssh", ...) or runSSHOutputArgs / runSSHScriptOutput calls outside of the daemon package
• This prevents future regressions where CLI code bypasses the daemon for remote operations
• Rule should live in the repo (e.g. .semgrep/no-direct-ssh-in-cli.yml) and run in CI

Acceptance criteria

• orch send <run> "message with ? and * chars" works without shell escaping issues
• All remote session operations route through the daemon protobuf protocol
• remote_control.go SSH helper functions are removed or moved into the daemon
• Semgrep rule blocks direct SSH calls from CLI code in CI
• No regression in local operation performance

🤖 Generated with Claude Code