phase 1: run-now backup — restic wrapper, job lifecycle, end-to-end

Lands the operator → server → agent → restic → server roundtrip for
on-demand backups. The flow:

  POST /api/hosts/{id}/jobs {kind:"backup",args:["/path"]}
    → server creates a queued Job row
    → server emits command.run over WS to the host's agent
    → agent dispatcher spawns runner.RunBackup in a goroutine
    → runner spawns `restic backup --json`, parses each line
    → forwards: job.started, log.stream (every line), job.progress
      (throttled to 1/sec), job.finished (with summary stats blob)
    → server WS handler persists those into jobs / job_logs

P1-16 internal/restic: thin Locate + Env wrapper that runs `restic
  backup --json`, scans stdout/stderr, parses BackupStatus +
  BackupSummary, calls back into a LineHandler so the agent can fan
  out to log.stream + job.progress. Treats exit code 3 as
  "succeeded with issues" (matches restic's contract).

P1-18 store: jobs accessors (CreateJob, MarkJobStarted,
  MarkJobFinished, AppendJobLog, GetJob).

P1-19 server: POST /api/hosts/{id}/jobs creates the Job row,
  validates kind, dispatches via Hub.Send, audit-logs the action.

P1-20 agent runner: wraps restic.RunBackup with throttled progress
  emission. Sender abstraction was added to wsclient.Handler so
  background goroutines can keep replying after dispatch returns.

P1-21 server WS: dispatchAgentMessage now persists job.started,
  job.finished, log.stream into the database. Browser fan-out for
  live tailing lands with the UI work.

Agent gets repo_url + repo_password from agent.yaml in plaintext
for now (mode 0600, owned by service user); spec.md §7.3's keyring
storage moves there in P2. config.update over WS overrides the
in-memory copy (does not persist).

Build clean; all tests pass. End-to-end with a real restic still
needs a host that has restic installed — wire shape verified by
the existing hello/heartbeat round-trip test.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

internal/server/http/server.go

@@ -83,6 +83,9 @@ func (s *Server) routes(r chi.Router) {
 		// /hosts/{id}/enrollment-token (regenerate) lands when the
 		// host page can call it; for now just the create endpoint.
 		r.Post("/enrollment-tokens", s.handleCreateEnrollmentToken)
+
+		// Run-now: dispatch a job to a host's agent.
+		r.Post("/hosts/{id}/jobs", s.handleRunNow)
 	})
 
 	// Agent ↔ server WebSocket. Bearer-authenticated inside the handler.