feat(discover): time-boxed suggestion snooze, server side — #2374

Migration 0049 adds suggestion_snoozes(user_id, candidate_mbid,
candidate_name, snoozed_until), and SuggestArtistsForUser excludes rows
whose snooze hasn't expired.

This is NOT a dislike. Rule #101 forbids a "Not for me" / thumbs-down
UI; a snooze is the approved shape instead because it records no verdict
on the music, expires on its own (~90d), and never reaches the taste
profile. It's acquisition triage — "not right now" — so the filter sits
at the candidate stage rather than in the score, where it would become a
ranking signal by the back door.

Per-user throughout (rule #47): one household member parking a candidate
leaves everyone else's deck untouched.

candidate_name is denormalized because suggestions are out-of-library by
definition — there is no artists row to resolve a display name from, and
the un-snooze list has to show something. That list is why GET
/discover/snoozes exists at all: a parked candidate is by definition
absent from the deck, so without it the DELETE would be unreachable.

Also fixes a hole in the codegen check from #2380: `git diff` ignores
untracked paths, so a brand-new generated file would have passed it
silently. `git add -N` first. This commit is the first to add one.

Endpoints:
  POST   /api/discover/suggestions/{mbid}/snooze  (body: name, days)
  DELETE /api/discover/suggestions/{mbid}/snooze
  GET    /api/discover/snoozes

UI lands in slice 4 (#2375) before any of this merges — rule #27.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

internal/api/suggestions.go

@@ -2,13 +2,19 @@ package api
 
 import (
 	"context"
+	"encoding/json"
+	"errors"
+	"io"
 	"net/http"
 	"strconv"
+	"strings"
 	"sync"
 
+	"github.com/go-chi/chi/v5"
 	"github.com/jackc/pgx/v5/pgtype"
 
 	"git.fabledsword.com/bvandeusen/minstrel/internal/apierror"
+	"git.fabledsword.com/bvandeusen/minstrel/internal/db/dbq"
 	"git.fabledsword.com/bvandeusen/minstrel/internal/lidarr"
 	"git.fabledsword.com/bvandeusen/minstrel/internal/recommendation"
 )
@@ -92,6 +98,150 @@ func (h *handlers) handleListSuggestions(w http.ResponseWriter, r *http.Request)
 	writeJSON(w, http.StatusOK, out)
 }
 
+// Snooze duration bounds. 90 days is long enough that a parked suggestion
+// stops feeling like it's nagging, short enough that a taste shift brings it
+// back on its own — the whole point of a snooze over a dismissal (#2374).
+const (
+	defaultSnoozeDays = 90.0
+	maxSnoozeDays     = 365.0
+)
+
+// snoozeRequest is the POST body. Both fields are optional in the JSON sense
+// (an absent body snoozes for the default), but Name is required in practice:
+// candidates are out-of-library, so the server has no artists row to resolve a
+// display name from and the un-snooze list would have nothing to show. The
+// client always has it — it just rendered the card.
+type snoozeRequest struct {
+	Name string  `json:"name"`
+	Days float64 `json:"days"`
+}
+
+// snoozeView is one row of GET /api/discover/snoozes.
+type snoozeView struct {
+	MBID         string             `json:"mbid"`
+	Name         string             `json:"name"`
+	SnoozedUntil pgtype.Timestamptz `json:"snoozed_until"`
+	CreatedAt    pgtype.Timestamptz `json:"created_at"`
+}
+
+// handleSnoozeSuggestion implements
+// POST /api/discover/suggestions/{mbid}/snooze.
+//
+// Parks a candidate for `days` (default 90, capped at 365). Idempotent:
+// snoozing an already-snoozed candidate extends it rather than conflicting.
+//
+// This is NOT negative feedback. It records no verdict on the artist and is
+// never read by internal/taste — see 0049_suggestion_snoozes.up.sql for the
+// rule #101 reasoning. Returns 204.
+func (h *handlers) handleSnoozeSuggestion(w http.ResponseWriter, r *http.Request) {
+	user, ok := requireUser(w, r)
+	if !ok {
+		return
+	}
+	mbid := strings.TrimSpace(chi.URLParam(r, "mbid"))
+	if mbid == "" {
+		writeErr(w, apierror.BadRequest("invalid_id", "missing mbid"))
+		return
+	}
+
+	// An empty body is a valid "snooze this for the default period", so EOF
+	// is not an error here — decodeBody would reject it as a malformed body.
+	var body snoozeRequest
+	if err := json.NewDecoder(r.Body).Decode(&body); err != nil && !errors.Is(err, io.EOF) {
+		writeErr(w, apierror.BadRequest("invalid_body", ""))
+		return
+	}
+	name := strings.TrimSpace(body.Name)
+	if name == "" {
+		writeErr(w, apierror.BadRequest("invalid_body", "name is required"))
+		return
+	}
+	days := body.Days
+	if days <= 0 {
+		days = defaultSnoozeDays
+	}
+	if days > maxSnoozeDays {
+		// Clamp rather than reject: a client asking for longer than we allow
+		// still means "park this", and failing the write would leave the card
+		// sitting there as if the tap did nothing.
+		days = maxSnoozeDays
+	}
+
+	q := dbq.New(h.pool)
+	if err := q.SnoozeSuggestion(r.Context(), dbq.SnoozeSuggestionParams{
+		UserID:        user.ID,
+		CandidateMbid: mbid,
+		CandidateName: name,
+		Column4:       days,
+	}); err != nil {
+		h.logger.Error("api: snooze suggestion", "err", err)
+		writeErr(w, apierror.InternalMsg("failed to snooze suggestion", err))
+		return
+	}
+	w.WriteHeader(http.StatusNoContent)
+}
+
+// handleUnsnoozeSuggestion implements
+// DELETE /api/discover/suggestions/{mbid}/snooze.
+//
+// Brings a parked candidate back immediately. 404s an MBID this user never
+// snoozed, so the client can tell "undone" from "there was nothing there".
+func (h *handlers) handleUnsnoozeSuggestion(w http.ResponseWriter, r *http.Request) {
+	user, ok := requireUser(w, r)
+	if !ok {
+		return
+	}
+	mbid := strings.TrimSpace(chi.URLParam(r, "mbid"))
+	if mbid == "" {
+		writeErr(w, apierror.BadRequest("invalid_id", "missing mbid"))
+		return
+	}
+	q := dbq.New(h.pool)
+	rows, err := q.UnsnoozeSuggestion(r.Context(), dbq.UnsnoozeSuggestionParams{
+		UserID:        user.ID,
+		CandidateMbid: mbid,
+	})
+	if err != nil {
+		h.logger.Error("api: unsnooze suggestion", "err", err)
+		writeErr(w, apierror.InternalMsg("failed to unsnooze suggestion", err))
+		return
+	}
+	if rows == 0 {
+		writeErr(w, apierror.NotFound("snooze"))
+		return
+	}
+	w.WriteHeader(http.StatusNoContent)
+}
+
+// handleListSuggestionSnoozes implements GET /api/discover/snoozes.
+//
+// The un-snooze surface needs this: a parked candidate is by definition
+// absent from the suggestion deck, so without a list there is no way to
+// reach the DELETE above. Scoped to the caller (rule #47). Expired rows are
+// already filtered by the query — the hourly gc sweep only reclaims space.
+func (h *handlers) handleListSuggestionSnoozes(w http.ResponseWriter, r *http.Request) {
+	user, ok := requireUser(w, r)
+	if !ok {
+		return
+	}
+	rows, err := dbq.New(h.pool).ListActiveSuggestionSnoozes(r.Context(), user.ID)
+	if err != nil {
+		h.logger.Error("api: list suggestion snoozes", "err", err)
+		writeErr(w, apierror.InternalMsg("failed to load snoozes", err))
+		return
+	}
+	out := make([]snoozeView, 0, len(rows))
+	for _, row := range rows {
+		out = append(out, snoozeView{
+			MBID:         row.CandidateMbid,
+			Name:         row.CandidateName,
+			SnoozedUntil: row.SnoozedUntil,
+			CreatedAt:    row.CreatedAt,
+		})
+	}
+	writeJSON(w, http.StatusOK, out)
+}
+
 // resolveSuggestionArt fills ImageURL on-demand from Lidarr's artist
 // lookup, matched by MBID (foreignArtistId). Best-effort and cache-free:
 // Lidarr is the only source — when it's disabled, unreachable, or has