Tasks: resume-on-respawn for tmux-hosted sessions

Phase 3 of 3 (requirements → design → tasks). DAG — a task starts once its dependencies are checked.

• [x] T1 — adapter contract. harness/base.py: interactive_resume_argv(prompt, session_id) raising UnsupportedRunnerError by default; harness/claude_code.py: --resume <id> … <prompt>. (AC1.1, AC1.4) — depends on nothing.
• [x] T2 — runner support. runner.py: TmuxRunner.spawn(..., resume=False) selecting the resume argv; survived(target, delay, sleeper=time.sleep) (no wait when delay <= 0) over has_live_session. (AC1.1, AC2.1, AC2.4, AC2.5) — depends on T1.
• [x] T3 — config mirror. TmuxConfig.resume_on_respawn (default true) and resume_probe_seconds (default 2.0) parsed from resumeOnRespawn / resumeProbeSeconds, hot-reloading with RoutingConfig. (AC1.3, AC4.1, AC4.2, AC4.3) — depends on nothing.
• [x] T4 — dispatcher resume-then-fall-back. _try_resume (opt-out, missing id, shape check, unsupported harness, failed spawn, dead pane → None) and _respawn_tmux using it: same id kept in the registry on success, uuid4() fresh spawn otherwise, existing failure handling untouched, still no announcement. (AC1.1, AC1.2, AC1.3, AC1.4, AC1.5, AC2.2, AC2.3, AC2.6) — depends on T2, T3.
• [x] T5 — observability. resumed on session.respawned; new session.resume_failed event type registered in eventlog.EVENT_TYPES; log lines distinguishing resumed vs fresh. (AC3.1, AC3.2, AC3.3) — depends on T4.
• [x] T6 — config schema + examples. resumeOnRespawn / resumeProbeSeconds under routing.tmux in .the-loop/cli-config.schema.json, plus the dogfood .the-loop/cli-config.yaml and the packaged skills/the-loop/templates/cli-config.yaml; make validate green. (AC4.1) — depends on T3.
• [x] T7 — unit tests. Adapter argv + unsupported-harness raise, runner resume spawn + survived, TmuxConfig parsing. — depends on T1–T3.
• [x] T8 — integration tests. Stub-tmux scenarios: respawn resumes the recorded id; a dead-on-arrival resume falls back to a fresh spawn carrying the same boot prompt; resumeOnRespawn: false respawns fresh; a resumed respawn posts no announcement. Update the issue-80/issue-86 respawn scenarios that asserted --session-id. — depends on T4, T5.
• [x] T9 — docs. cli/README.md config table rows; docs/capabilities/interactive-sessions.md behaviour bullet + history row. — depends on T4, T6.
• [x] T10 — gates. make check fully green; evidence in execution-log.md; PR + reviewer briefing. — depends on T1–T9.