docs: add environment reference and bug investigation report

environment.md:
- Documents CT104 as the active development location
- Lists SSH access, repository paths, and service commands
- Notes that cortex clone is parked, matt-desktop has no clones

BUG-CADENCE-DECREASE.md:
- Full investigation of the cadence-decrease hot-reload bug
- Root cause analysis: cancel_event.set() inside lock context
- Proposed fix (Option A - structural)
- Test gap identification
- Production verification steps

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

docs/environment.md

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+# Central Data Hub - Environment Reference
+
+## Development Locations
+
+### Active Development: CT104 (Central LXC)
+
+All development work happens on the Central LXC container:
+
+| Property | Value |
+|----------|-------|
+| **Hostname** | `central` |
+| **Tailscale IP** | `100.64.0.12` |
+| **LAN IP** | `192.168.1.104` |
+| **SSH access** | `zvx@central` or `zvx@100.64.0.12` |
+| **Repository path** | `/opt/central` |
+| **Python venv** | `/opt/central/.venv` |
+| **Services** | `central-supervisor`, `central-archive` |
+
+### Parked Clone: Cortex
+
+The cortex VM at `/home/zvx/projects/central` contains a clone that is
+**not actively used for development**. It may be retired in the future.
+Do not make changes there.
+
+### Local Workstation: matt-desktop
+
+The Windows workstation (matt-desktop) has no Central repository clones.
+The directory `C:\Users\mtthw\central_work\` is scratch space only and
+should not be used for commits.
+
+## Repository
+
+| Property | Value |
+|----------|-------|
+| **Origin** | `git@github.com:zvx-echo6/central.git` |
+| **Main branch** | `main` |
+| **Default user** | `central` (on CT104) |
+
+## Services
+
+### central-supervisor
+
+The main adapter scheduler and event publisher. Polls upstream APIs,
+normalizes events, and publishes to NATS JetStream.
+
+```bash
+# Status
+systemctl status central-supervisor
+
+# Logs
+journalctl -u central-supervisor -f
+
+# Restart (requires sudo)
+sudo systemctl restart central-supervisor
+```
+
+### central-archive
+
+Consumes events from NATS JetStream and archives to PostgreSQL/TimescaleDB.
+
+```bash
+# Status
+systemctl status central-archive
+
+# Logs
+journalctl -u central-archive -f
+```
+
+## Database
+
+PostgreSQL 16 with TimescaleDB runs on CT104:
+
+```bash
+# Connect as central user
+psql -h localhost -U central -d central
+
+# Check adapter config
+SELECT name, cadence_s, enabled FROM config.adapters;
+
+# Check recent events
+SELECT id, time, category FROM events ORDER BY time DESC LIMIT 10;
+```
+
+## SSH Access from Windows
+
+From matt-desktop, connect via Tailscale:
+
+```bash
+# Direct connection
+ssh zvx@100.64.0.12
+
+# Using hostname (if Tailscale DNS configured)
+ssh zvx@central
+```
+
+Note: The `zvx` user requires password for sudo operations.