Add diagram workbench UI with Modelica DoF coaching and ISO glyphs.

Ship the Next.js cycle editor with CAD chrome, technical HX symbols, Fixed/Free boundary guidance, and secondary water/air pressure drop support in the solver stack.

Co-authored-by: Cursor <cursoragent@cursor.com>

apps/web/public/docs/components/evaporator.md

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+# Evaporator / EvaporatorCoil
+
+Config types: `"Evaporator"`, `"EvaporatorCoil"`  
+Source: `crates/components/src/heat_exchanger/evaporator.rs`
+
+---
+
+## EN
+
+### Purpose & physical model
+
+**DX (direct-expansion)** evaporator: refrigerant outlet is **superheated vapor** (not flooded two-phase). Phase-change ε-NTU against a hot secondary stream:
+
+```
+ε = 1 − exp(−UA / C_sec)
+Q = ε · C_sec · (T_sec,in − T_evap(P))     # heat absorbed by refrigerant
+```
+
+- Optional refrigerant ΔP = k·ṁ·|ṁ|  
+- `EvaporatorCoil` locks secondary side to **Air**  
+- **No plate correlation** (see BPHX / Longo–Shah for geometry-based UA)
+
+Difference vs `FloodedEvaporator`: DX uses **superheat closure** (or regulated SH); flooded uses **saturated vapor** (or quality) by default.
+
+### Dual secondary modes (Newton)
+
+| Mode | Secondary | `n_secondary` |
+|------|-----------|---------------|
+| **System** | Live `secondary_inlet` / `secondary_outlet` | 1 or 2 |
+| **Rating** | Scalars T_sec + C_sec (ṁ·cp) | 0 |
+
+`coupled_ready` = refrigerant ready **and** (live edges **or** rating scalars).  
+`live_secondary_stream` = edges first, else rating scalars.
+
+### Residuals & `n_equations()` (coupled emergent)
+
+| Row | Equation |
+|-----|----------|
+| r0 | `P_out − (P_in − ΔP)` (optional skip) |
+| r1 | `ṁ · (h_out − h_in) − Q` |
+| r2 | `h_out − h(P, T_evap+SH)` if superheat is imposed |
+| r_mass | dropped if same-branch |
+| r_sec | live secondary mass/energy if edges |
+
+```
+n_thermo = base (1 or 2) + 1 if imposes_superheat()
+n_equations = n_thermo + mass? + n_secondary
+```
+
+### Superheat regulation (DoF)
+
+| Setting | Effect |
+|---------|--------|
+| Default | SH residual active (`superheat_k` target) when emergent |
+| `superheat_regulated: true` | **Drops** SH residual (−1 eq) |
+
+If SH residual is dropped, pair with a **free** EXV opening (and usually a control loop) so the system stays square. CLI DoF gate enforces balance.
+
+### Ports
+
+| Port | Index |
+|------|-------|
+| `inlet` / `outlet` | 0 / 1 refrigerant |
+| `secondary_inlet` / `secondary_outlet` | 2 / 3 secondary |
+
+### Calibration
+
+| Factor | Default | Notes |
+|--------|---------|-------|
+| `z_ua` | **1.0** | UA scale |
+| `z_dp` | 1.0 | ΔP scale |
+
+UI Fixed: SST (`saturationTemperature`) + free `z_ua` for inverse calib.
+
+### JSON parameters (main)
+
+| Key | Meaning | Default |
+|-----|---------|---------|
+| `ua` | UA [W/K] | required |
+| `emergent_pressure` | free P_evap | false |
+| `superheat_k` | SH target [K] | 5 |
+| `superheat_regulated` | drop SH residual | false |
+| `secondary_fluid` / `secondary_*` | system edges or rating | – |
+| `skip_pressure_eq` | drop ΔP residual | false |
+
+### energy_transfers
+
+Coupled: `Q = ṁ·(h_out − h_in)` as positive heat (cooling capacity).
+
+### Zero flow
+
+Smooth `|ṁ|` for live `C_sec`; no silent mass-index→pressure fallback.
+
+---
+
+## FR
+
+### But & modèle
+
+Évaporateur **DX** (sortie **surchauffée**). Duty ε-NTU :
+
+```
+Q = ε · C_sec · (T_sec,in − T_evap(P))
+```
+
+Différence avec **FloodedEvaporator** : clôture **superheat**, pas vapeur saturée noyée.
+
+### Modes secondaire
+
+- **Système :** ports live  
+- **Rating :** scalaires T + ṁ·cp **dans le Newton**
+
+### Régulation de surchauffe
+
+`superheat_regulated: true` enlève le résidu SH → **libérer** l’ouverture EXV (contrôle).
+
+### Calibration
+
+`z_ua = 1` par défaut. Fixed SST + Z_UA libre pour calage.
+
+### Ports / JSON
+
+Voir EN.