feat(ttp): E.4.a extract decnet/cli/ttp.py with worker run + backfill CLI

The TTP worker entry moved out of decnet/cli/workers.py into its own
module so the TTP CLI surface (worker + admin verbs) is colocated,
mirroring decnet/cli/canary.py / webhook.py / swarm.py.

- New `decnet/cli/ttp.py` with `decnet ttp` (worker, ExecStart-stable
  for decnet-ttp.service) and `decnet ttp-backfill --since-days N`.
- `decnet ttp-backfill` walks Attacker.commands and CanaryTrigger
  history, dispatches each row through the live CompositeTagger,
  persists tags via repo.insert_tags (idempotent INSERT OR IGNORE).
  --dry-run / --source command|canary|all / --batch-size supported.
- Backfill deliberately bypasses bus publish — historical replay
  must not re-trigger SIEM/webhook fan-out per TTP_TAGGING.md
  §"Bus topics" loop-prevention invariant.
- Added `iter_attacker_commands_since` / `iter_canary_triggers_since`
  read-only iterators on TTPMixin + abstract bindings on
  BaseRepository.
- Master-only via gating; both `ttp` and `ttp-backfill` listed in
  MASTER_ONLY_COMMANDS.

decnet/cli/__init__.py

@@ -39,6 +39,7 @@ from . import (
     swarm,
     swarmctl,
     topology,
+    ttp,
     updater,
     web,
     webhook,
@@ -59,7 +60,7 @@ for _mod in (
     swarm,
     deploy, lifecycle, workers, inventory,
     web, profiler, orchestrator, realism, reconciler, sniffer, db,
-    topology, bus, geoip, init, webhook, canary,
+    topology, bus, geoip, init, webhook, canary, ttp,
 ):
     _mod.register(app)