feat: slskd reconnect guard in downloaders_reset, mass v2 sync

- downloaders_reset: connection check block before slskd API sections;
  triggers PUT /api/v0/server reconnect if disconnected, polls 60s,
  gates Stuck Searches and Dead Transfer Records on SLSKD_CONNECTED
- Sync all modified/new/deleted files from v2 refactor across Docker_Essentials,
  Media, Monitors, Partnership, Rsync, Tools, Transcodes, unRAID_Essentials,
  common.sh, master confs, and new Manual/README docs

Kernel/README-Kernel.md

@@ -0,0 +1,91 @@
+# ━━━━━ KERNEL ━━━━━
+
+Shared intelligence layer for media automation. Sourced by consumer scripts —
+not run directly. Contains stateful scoring systems, adaptive logic, and
+cross-domain engines that would pollute common.sh if placed there.
+
+---
+
+## ━━━ WHAT THIS FOLDER IS ━━━
+
+**Not scripts. Not utilities. Engines.**
+
+The Kernel holds logic that is:
+
+- **Stateful** — maintains scores, decay state, or adaptive thresholds across calls
+- **Domain-aware** — understands the difference between music, TV, and movie decisions
+- **Shared across consumers** — one engine, multiple discovery scripts consuming it
+
+This is distinct from:
+
+| Location | Contains |
+|----------|----------|
+| `common.sh` | Reusable utility functions (logging, locking, arg parsing) |
+| `master.conf` | Shared ecosystem configuration and tuning values |
+| `Kernel/` | Stateful scoring systems and adaptive decision logic |
+
+The rule: if the logic makes *decisions*, it lives here. If it's a helper or
+config value, it lives in common.sh or master.conf.
+
+---
+
+## ━━━ WHY A SEPARATE KERNEL ━━━
+
+Media automation decisions are not uniform. A Lidarr discovery script should be
+highly selective. A Sonarr intake script should be family-aware and balanced. A
+Radarr script should be broadly flexible. If scoring logic lives in each script,
+it diverges and drifts independently.
+
+Centralizing the decision layer:
+
+- Keeps consumers thin — they define weights and thresholds, not scoring logic
+- Prevents cross-domain bias pollution — music strictness does not contaminate TV
+- Allows the scoring model to improve without touching every consumer script
+
+---
+
+## ━━━ WHAT BELONGS HERE ━━━
+
+An engine belongs in Kernel if it:
+
+- Implements a scoring or evaluation model
+- Maintains or reads adaptive state
+- Is consumed by more than one script (or is designed to be)
+- Contains logic that would create tight coupling if duplicated
+
+Utilities — locking, notifications, arg parsing, API calls — belong in common.sh.
+
+---
+
+## ━━━ FILES IN THIS FOLDER ━━━
+
+| File | Role | Status |
+|------|------|--------|
+| `decision_engine.sh` | Behavior-driven scoring kernel — scoring, decay, deduplication, threshold evaluation | WIP — currently paired with `playback_aware_lidarr_discovery.sh` |
+
+**Planned:**
+
+| File | Role |
+|------|------|
+| `transcoding_engine.sh` | Transcoding decision logic (quality, codec selection, cost-benefit evaluation) |
+
+---
+
+## ━━━ HOW CONSUMERS USE THE KERNEL ━━━
+
+Source the engine at the top of the consumer script:
+
+```bash
+source "$ROOT_DIR/Kernel/decision_engine.sh"
+```
+
+Then call engine functions directly, passing consumer-defined weights and thresholds:
+
+```bash
+score=$(score_candidate "$user_score" "$popularity" "$recency" "$quality")
+score=$(apply_temporal_decay "$score" "$age_days")
+decision=$(make_decision "$score" "$MY_THRESHOLD")
+```
+
+The engine returns values — consumer scripts decide what to do with them. The
+engine has no side effects: no file writes, no API calls, no deletions.