docs(tools): local ComfyUI, how to start it, and the checkpoint pair it actually has

Tools/README.md now covers the generative tools next to each other:

- comfyui_generate.py drives the LOCAL ComfyUI at 127.0.0.1:8188, which this repository does not start. A new
  subsection says so and says what to do: start Stability Matrix, launch ComfyUI, re-run. It points at
  /home/zwitschi/StabilityMatrix/Data/README.md for the package version, the launch arguments and the shared
  80 GB model library, and notes that THIRD_PARTY_NOTICES.md must carry the model and licence before a
  generated texture ships.
- generate_facade_textures.py and generate_character_textures.py are listed as the deterministic procedural
  path: no model, no network, byte-identical on every run.
- The tool's own docstring carries the same Stability Matrix instruction.

The default second checkpoint was sd_xl_base_1.0.safetensors, which is NOT installed; it is now
epicrealismXL_pureFix.safetensors, verified against the running server. The pair was smoke-tested end to end
at 512 px: both checkpoints rendered, both scored, juggernautXL won at 20.37 against 12.93, and the winner
landed on --out with the loser kept beside it.

Tools/README.md

@@ -85,9 +85,20 @@ Geographic tools live in [`Geo/tools/`](../Geo/README.md) and the Blender-side b
 
 | Tool | Purpose |
 | --- | --- |
+| `comfyui_generate.py` | Drives the **local** ComfyUI at `http://127.0.0.1:8188` (Stability Matrix install): `models` lists checkpoints, `txt2img` renders through the HTTP API and writes a provenance sidecar (model, prompt, seed, full graph). Two checkpoints by default — same prompt and seed, both scored by high-frequency detail, the winner takes `--out`, the loser is kept as `<out>__<model>.png`. `--alt-model ""` for a single run. Local and human-triggered; no credential. |
+| `generate_facade_textures.py` | Procedural, deterministic facade texture maps (ashlar base colour + roughness, stucco, asphalt, concrete) written with a pure-zlib PNG encoder — no model, no network, byte-identical on every run. |
+| `generate_character_textures.py` | Procedural character texture maps, same deterministic approach as the facade set. |
 | `facade_detail_concepts.py` | Generates **frontal building plates** (whole elevation, entrance in its facade, or building with neighbours) from a local reference photograph with an image model (OpenRouter); close-up detail crops are deliberately not requested because they cannot be measured for proportion. `--list` is free and shows which studies have their reference present; `--all`/`--only <name>` generates. Never overwrites (writes `-v2`, `-v3`), writes a `.refgen.json` sidecar per image (model, prompt, source photo, SHA-256), and puts everything under `Art/reference/facade-details/` — gitignored, local-only, never shipped. Costs money per image, so it is never automatic. |
 | `judge_screenshot.py` | (see Visual review) |
 
+### Local image generation: start Stability Matrix first
+
+`comfyui_generate.py` talks to ComfyUI on `http://127.0.0.1:8188`. That server is **not** started by this repository — it lives in a [Stability Matrix](https://lykos.ai) install and must already be running.
+
+**If the tool reports a connection error, start Stability Matrix and launch ComfyUI**, then re-run. The install is documented in [`/home/zwitschi/StabilityMatrix/Data/README.md`](/home/zwitschi/StabilityMatrix/Data/README.md): package version, launch arguments, and the shared model library (`Models/`, ~80 GB, mapped in through `extra_model_paths.yaml`). Reading that file before writing a prompt is the cheap way to see which checkpoints actually exist — `python3 Tools/comfyui_generate.py models` asks the running server the same question, and it is the authoritative list — the default pair is `juggernautXL_ragnarok.safetensors` and `epicrealismXL_pureFix.safetensors`, both verified installed.
+
+Checkpoints are **not** committed. A generated texture ships only after its model and licence are recorded in [`THIRD_PARTY_NOTICES.md`](../THIRD_PARTY_NOTICES.md); the sidecar carries what that needs.
+
 ## Input injection
 
 | Tool | Purpose |