feat(P01): SSH-push transport layer — connection pool, retry, fan-out, idempotent writes (REQ-073)
P01 — Load-bearing replacement for v0.8 mTLS transport (R-001).
Transport (internal/sshpush/transport.go, REQ-073):
- Transport struct with sync.Map connection pool (reuse *ssh.Client per peer).
- Exec with context timeout (10s default) + retry (100ms x2 cap 5s max 5
attempts, +/-25% jitter — same backoff as v0.8 transport/retry.go).
- ReadFile, WriteFile (atomic heredoc + mv), Close.
- sshDialer + sshSession seams for testability. TOFU host-key verification
reuses proxmox.TOFUHostKeyCallback. security.Flock for known_hosts.
Fan-out (internal/sshpush/fanout.go):
- ExecAll, WriteAll with errgroup + SetLimit semaphore (default 8 per I-B-001).
Per-peer errors collected, don't cancel the group.
Idempotency (internal/sshpush/idempotency.go, C-18):
- WriteFileIdempotent: SHA-256 compare via ssh sha256sum; skip if content
matches (written=false). Content-addressed idempotency replaces the v0.8
X-Orca-Idempotency-Key header (C-18 capability map).
Tests: in-process fake SSH server (ssh.NewServerConn NoClientAuth ed25519)
for e2e + interface seams for pure-logic. 93.0% coverage. 20 packages pass.
---ci---
project: orca
phase: P01
milestone: v0.9
status: execute
---/ci---
Jon Chery
e92b18197c