Add idea actions: add to Quest log and cook tonight (Feature 18)

POST /api/v1/ideas/{jobId}/items/{i}/quest-log adds idea i of a
succeeded ideas job to the Quest log as a dinner grounded in the idea's
own recipe, with origin ingredients or quick, or answers the dinner it
repeats as it is (the Regular dedupe rule), so repeating the call is
idempotent. POST .../cook-tonight does the same, then puts the dinner on
today (household timezone) of this week's plan through plan.Service.Swap;
with no plan for the week it answers 409 no_plan and changes nothing.

Maestro task 54dcd487-1597-4a91-8493-97f3a7635e2d.

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

docs/ARCHITECTURE.md

@@ -363,6 +363,34 @@ automatic** (D-021).
   idea is kept, fails with the same reasons, and a failed job shows no
   ideas through the same `FailedResult` view. "↻ Show me more" posts
   again with every name the tab has shown so far in `exclude`.
+- Idea actions (Feature 18). Both act on idea `{i}` (0, 1, …; anything
+  else is 400 `invalid_request`) of a **succeeded** `ideas_from_ingredients`
+  or `quick_ideas` job, read from its stored result
+  (`ideas.Service.Idea`): its name and `recipe_id`, never grounded again.
+  A job still queued or running is 409 `ideas_not_ready` (its ideas may
+  still move); an unknown job, another kind, a failed job or an index past
+  its ideas is 404 `not_found`. `POST
+  /api/v1/ideas/{jobId}/items/{i}/quest-log` (no body) runs
+  `dinners.Service.AddToQuestLog`: in one transaction, an unarchived
+  dinner the idea repeats — the same rule that refuses a duplicate Regular
+  (`harness.Similar` name, or the recipe's link) — is answered 200 as it
+  is (a Regular stays a Regular); one awaiting the household's choice
+  (`suggested`, `tried`) is 409 `duplicate_dinner` and changes nothing;
+  otherwise it creates a dinner with status `quest_log`, origin
+  `ingredients` or `quick`, grounded in the idea's recipe (its method,
+  minutes, difficulty and photo), answered 201. Repeating the call
+  answers the same dinner. `POST /api/v1/ideas/{jobId}/items/{i}/cook-tonight`
+  (no body) takes today as the household-local date in the household
+  timezone and its Monday (`plan.Service.Tonight`); when that week has no
+  plan it answers 409 `no_plan` and changes nothing — no dinner, no plan
+  (a plan holds all seven days; the household plans the week first).
+  Otherwise it adds or finds the dinner as `quest-log` does and puts it
+  on today through `plan.Service.Swap`, exactly like a Draft board swap
+  (plan marked edited, revision raised, a synced plan becomes `changed`,
+  the day's calendar event id cleared, `is_new` for a Quest log dinner),
+  answering 200 `{dinner, plan}`. The week is always today's own, so no
+  other day is written; a dinner already on another day of the week is
+  409 `dinner_already_planned`.
   `GET /api/v1/suggestions/deck` returns `{suggestions: [{id, dinner_id,
   name, photo_url, difficulty, method, minutes_total, cuisine, reason,
   cited_regular_ids, status, dinner_status, decided_at, created_at}],