tools: add physics-sanity + Docker MCP scaffolding + tools/README

- tools/physics-sanity/ — JS library of cross-node balance helpers
  (mass / hydraulic / hydraulic-power / oxygen-transfer / energy) with
  7 unit tests + a CLI demo. Designed for `require()` from per-node
  integration tests where shape-based unit tests miss physically-
  impossible plant states.
- tools/docker-compose.yml + tools/mcp/{node-red-admin,influxdb,browser}
  scaffolding — placeholder Dockerfiles + a ROADMAP.md for the Node-RED
  admin MCP. Compose file is the target shape for the Q3-2026 migration
  to the central MCP server; the per-service Dockerfile stays in this
  repo as the canonical definition either way. Implementations are TODO.
- tools/README.md — top-level tooling index; documents the CI order for
  running every tool on a PR.
- .gitignore: ignore tools/.env (developer-specific MCP endpoints).

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

tools/physics-sanity/README.md

@@ -0,0 +1,80 @@
+# @evolv/physics-sanity
+
+Cross-node physical-balance helpers. Import from any node's test files
+to assert that scenario states close mass, hydraulic, hydraulic-power,
+oxygen-transfer, or energy balances within a stated tolerance.
+
+## Why
+
+Per-node unit tests verify shape and behaviour. They don't catch
+physically impossible plant states that arise from cross-node coupling
+— e.g. a pumpingStation reporting outflow > inflow + accumulation, or a
+diffuser reporting OTR inconsistent with its KLa × ΔC × V.
+
+These helpers don't replace per-node tests. They sit on top of an
+integration scenario and assert the closing balance.
+
+## Usage
+
+```js
+const sanity = require('../../../tools/physics-sanity');
+
+test('three-pump station closes the hydraulic balance', () => {
+  // … drive the scenario, take a snapshot …
+  const r = sanity.assertHydraulicBalance({
+    headerSuctionPa: ps.suctionPressurePa,
+    headerDischargePa: ps.dischargePressurePa,
+    pumpHeadPa: sumOfPumpHeads,
+    frictionPa: pipeFrictionEstimate,
+  });
+  assert.equal(r.ok, true, sanity.reportToString(r));
+});
+```
+
+## Helpers exported
+
+| Function | Asserts |
+|---|---|
+| `assertMassBalance({ inflowKgPerS, outflowKgPerS, accumulationKgPerS })` | `in - out - accumulation ≈ 0` |
+| `assertHydraulicBalance({ headerSuctionPa, headerDischargePa, pumpHeadPa, frictionPa, staticHeadPa })` | `ΔP_headers ≈ pumpHead - friction - static` |
+| `assertHydraulicPower({ flowM3PerS, headPa, shaftPowerW, efficiency })` | `shaft ≈ Q·H / η` |
+| `assertOxygenTransfer({ klaPerS, csMgPerL, cMgPerL, otrKgPerS, volumeM3 })` | `OTR ≈ KLa · (Cs - C) · V` |
+| `assertEnergyBalance({ heatInW, workInW, heatOutW, workOutW, accumulationW })` | `Q_in + W_in ≈ Q_out + W_out + ΔE` |
+
+Each returns `{ ok, label, ...residuals }`. `reportToString(r)` formats
+for human-readable failure messages.
+
+## CLI demo
+
+```bash
+node tools/physics-sanity/bin/physics-sanity.js
+```
+
+Runs four sanity-check scenarios against the helpers (smoke-test for
+the library itself).
+
+## Tolerance defaults
+
+| Domain | Absolute | Relative |
+|---|---|---|
+| mass | 1e-6 kg/s | 0.1 % |
+| hydraulic ΔP | 50 Pa (0.5 mbar) | 0.1 % |
+| hydraulic power | 1 W | 0.5 % |
+| OTR | 1e-4 kg/s | 0.5 % |
+| energy | 1 W | 0.1 % |
+
+Override per call with `absTol` / `relTol`.
+
+## Where to use this
+
+Out-of-the-box destinations:
+
+| Scenario | Where to add | Calls |
+|---|---|---|
+| pumpingStation hydraulic closure | `nodes/pumpingStation/test/integration/` | `assertHydraulicBalance`, `assertHydraulicPower` |
+| reactor → settler mass balance | `nodes/reactor/test/integration/` | `assertMassBalance` |
+| diffuser OTR vs reactor uptake | `nodes/diffuser/test/integration/` | `assertOxygenTransfer` |
+| machineGroupControl efficiency sanity | `nodes/machineGroupControl/test/integration/` | `assertHydraulicPower` |
+
+A future tool can scan integration tests and report which scenarios do
+or don't have a closing-balance assertion.