docs: add cooking log design spec

.gitignore

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 .pi/
 __pycache__
 .worktrees/
+.superpowers/

docs/specs/2026-05-25-cooking-log-design.md

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+# Cooking Log Design
+
+Record dates and comments when cooking a recipe, viewable on the recipe page
+and across all recipes by date.
+
+## Data Model
+
+### SQLite schema
+
+A single `cook_log` table:
+
+```sql
+CREATE TABLE IF NOT EXISTS cook_log (
+    id              INTEGER PRIMARY KEY AUTOINCREMENT,
+    recipe_filename TEXT NOT NULL,
+    cooked_date     TEXT NOT NULL,   -- ISO date (YYYY-MM-DD)
+    comment         TEXT NOT NULL DEFAULT '',
+    created_at      TEXT NOT NULL    -- ISO datetime
+);
+
+CREATE INDEX idx_cook_log_recipe ON cook_log(recipe_filename);
+CREATE INDEX idx_cook_log_date   ON cook_log(cooked_date DESC);
+```
+
+- `recipe_filename` is the lowercased filename with `.cook` stripped,
+  matching the key used by the recipe index.
+- `cooked_date` stores the user-picked date (not necessarily today).
+- `comment` is optional (defaults to empty string).
+
+### Haskell types
+
+New module `Roux.CookLog`:
+
+```haskell
+data CookEntry = CookEntry
+    { ceId             :: Int
+    , ceRecipeFilename :: Text
+    , ceCookedDate     :: Day
+    , ceComment        :: Text
+    , ceCreatedAt      :: UTCTime
+    }
+```
+
+- `Day` (from `Data.Time.Calendar`) for dates.
+- `UTCTime` for `created_at`.
+
+## API Endpoints
+
+All routes live in `Roux.Server` following existing patterns.
+
+| Method | Path | Purpose |
+|--------|------|---------|
+| `POST /cook-log/{filename}` | Record a cooking event | Form body: `cooked-date` (required, YYYY-MM-DD) + `comment` (optional). Returns JSON `{ ok: true }` on success, `{ error: "..." }` on failure. Multiple entries for the same date are allowed — no uniqueness constraint. |
+| `GET /cook-log/{filename}` | Fetch entries for one recipe | JSON array of `CookEntry`, sorted by `cooked_date DESC` |
+| `GET /cook-log` | Fetch all entries | JSON array of `CookEntry` with recipe info, sorted by `cooked_date DESC`, for cross-date view |
+
+### DB connection
+
+SQLite database file at `<recipeDir>/cook-log.db`. Opened once at server
+startup, passed to handlers via a shared value (same `IORef` pattern as the
+recipe state map).
+
+### Library: `sqlite-simple`
+
+Minimal dependency. Pure SQL, typed results via `FromRow` instances.
+
+```
+dependencies:
+  - sqlite-simple
+```
+
+## Frontend Rendering
+
+### "I cooked this" form at the top of the marginalia section
+
+```html
+<h2>Cook history</h2>
+<form class="roux-cook-log-form" data-filename="pancakes">
+  <input type="date" name="cooked-date" value="2026-05-25">
+  <input type="text" name="comment" placeholder="Optional note..." maxlength="500">
+  <button type="submit">Log it</button>
+</form>
+```
+
+- `<input type="date">` gives a native date picker, defaults to today.
+- Comment is an optional text input, max 500 chars.
+- Form POSTs via `fetch()` with `FormData`, no page reload.
+- On success, JS appends the new entry to the entry list below.
+- On error, JS shows the error message inline.
+
+### Entry list in the marginalia column
+
+```
+── Mar 15 ──
+Used baking powder instead of soda, turned out fine
+
+── Mar 2 ──
+Added extra vanilla
+
+── Feb 20 ──
+```
+
+Rendered style:
+- Date centered between dashes, bold/small.
+- Comment below, plain text.
+- No comment = just the date separator line.
+
+### Recipe page rendering
+
+`recipePage` in `Html.hs` accepts cook entries as an additional parameter
+(or fetches them server-side during page render). The log section renders
+inside the marginalia column, after Tags and before Notes.
+
+### JavaScript
+
+Lightweight inline script (new constant alongside `recipeImageUploadJs`):
+
+```javascript
+document.querySelector('.roux-cook-log-form').addEventListener('submit', async (e) => {
+  e.preventDefault();
+  const form = e.target;
+  const fd = new FormData(form);
+  const res = await fetch('/cook-log/' + form.dataset.filename, { method: 'POST', body: fd });
+  if (!res.ok) return;
+  const entry = await res.json();
+  // Prepend rendered entry to the list
+});
+```
+
+## Cross-Date View
+
+- Page at `/cook-history` showing all log entries grouped by month,
+  newest first.
+- Each entry shows: date, recipe name (linked), comment (if any).
+- Accessible from a link in the main navbar ("Cook History").
+- SSR rendered (no additional JS needed).
+
+## Implementation Order
+
+1. Add `sqlite-simple` dependency and `Roux.CookLog` module (types + DB ops)
+2. Initialize DB at server startup (create table, open connection)
+3. Implement POST/GET endpoints for single-recipe log entries
+4. Integrate cook log entries into recipe page SSR in marginalia column
+5. Add "I cooked this" form with JS submit handler
+6. Implement cross-date view at `/cook-history`
+7. Add nav link to cook history