feat(enhance): LoRA switches per template (#218)

A template can offer optional LoRAs the app turns on or off.

- enhance.toml: [[template.lora]] { id, label, default } per template.
  Each id drives every workflow node titled `imageapi:lora:<id>`, so
  Wan's high- and low-noise pair share one switch.
- POST /enhance takes `loras: {id: bool}`; a missing id uses its default,
  an id the template doesn't offer is a 400. Off sets strength_model
  (and strength_clip when present) to 0, so the graph is never rewired.
- The resolved switches are stored on the job (new enhance_jobs.loras
  JSON column) and returned in the job view, so a retry or adjust can
  repeat them; GET /enhance/templates lists each template's switches.
- A lora-titled node without a declaration keeps its exported strength,
  and a declaration without nodes isn't offered; both are startup
  warnings. A lora-titled node without a numeric strength_model fails
  the template.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

CLAUDE.md

@@ -459,14 +459,19 @@ auth and stays LAN-only, so ImageApi relays previews too.
   Keys: `url`, `timeout_secs`, `probe_ttl_secs`, `poll_secs`, `idle_free_secs`,
   `unreachable_grace_secs`, `default_template`, `warn_above_megapixels`,
   `[[path_map]]` (`from`, `to`), `[[template]]` (`name`, `label`, `description`,
-  `file`, `prompt_mode`, `prompt_join`, `output_megapixels`).
+  `file`, `prompt_mode`, `prompt_join`, `output_megapixels`, `[[template.lora]]`
+  (`id`, `label`, `default`)).
 - **Templates** are API-format workflow exports, read-only (never edit them from
   here). Nodes are found by `_meta.title`: `imageapi:source` (required, gets the
   photo path), `imageapi:save` (required, forced to `require_approval = true`; a
   `ImageApiSaveVideoVersion` there makes the template's `output` `video`, an MP4 clip,
   else `image`),
   `imageapi:prompt` (optional; fills the first of `text` / `prompt` / `value`),
-  `imageapi:reference` (optional). `prompt_mode = "append"`: the user's text is joined
+  `imageapi:reference` (optional), `imageapi:lora:<id>` (optional LoRA switches, #218:
+  a declared `[[template.lora]]` id drives every node with that title, e.g. Wan's high and
+  low pair; off = `strength_model`/`strength_clip` set to 0, never rewired; a node with no
+  declaration keeps its strength, a declaration with no node isn't offered; both log a
+  startup warning). `prompt_mode = "append"`: the user's text is joined
   after the template's own prompt with `prompt_join` (default one space); empty text
   leaves the prompt as is. `"replace"`: the text *is* the prompt and is required (empty
   = 400); it needs a prompt node. With no `reference_path` the reference node **and
@@ -512,8 +517,10 @@ GET  /enhance/templates
       "templates": [{"name","label","description","accepts_prompt",
                      "prompt_mode": "append"|"replace", "prompt_required",
                      "accepts_reference","default","output_megapixels",
-                     "warn_above_megapixels", "output": "image"|"video"}]}
-POST /enhance  {"path","template","prompt"?,"reference_path"?,"library"?}  -> job
+                     "warn_above_megapixels", "output": "image"|"video",
+                     "loras": [{"id","label","default"}]}]}
+POST /enhance  {"path","template","prompt"?,"reference_path"?,"loras"?: {id: bool},"library"?}  -> job
+     (a missing switch uses its default; an id the template doesn't offer = 400)
 GET  /enhance/jobs/{id}              -> job
 GET  /enhance/jobs?path=&library=    -> {"jobs": [job, ...]}  newest first, discarded hidden
 GET  /enhance/jobs[?status=a,b]       -> {"jobs": [...]}  no path = the jobs manager: every photo's
@@ -530,7 +537,8 @@ POST /enhance/jobs/{id}/approve {"n"} -> a /image/versions `versions[]` (or `cli
 POST /enhance/jobs/{id}/discard      -> job (hidden from the list; ComfyUI untouched)
 
 job = {"id","status","queue_position"?,"error"?,"path","library_id","template",
-       "prompt"?,"reference_path"?,"created_at","updated_at",
+       "prompt"?,"reference_path"?,"loras"?: {id: bool} (resolved; absent without switches),
+       "created_at","updated_at",
        "run_ms": <ms ComfyUI ran it, or null until finished / when ComfyUI gave no timings>,
        "pending": [{"n","preview": "/enhance/jobs/{id}/preview/{n}","approved"}],
        "saved":   [{"n","path","library_id"}]}