feat(wiki): add community image upload for wiki entities

Support uploading images for Pokemon, Items, and Habitats
Track upload history in new entity_image_uploads table
Update entity cards to display uploaded images and usage ribbons

backend/db/schema.sql

@@ -330,11 +330,13 @@ CREATE TABLE IF NOT EXISTS items (
   dual_dyeable boolean NOT NULL DEFAULT false,
   pattern_editable boolean NOT NULL DEFAULT false,
   no_recipe boolean NOT NULL DEFAULT false,
+  image_path text NOT NULL DEFAULT '',
   sort_order integer NOT NULL DEFAULT 0 CHECK (sort_order >= 0)
 );
 
 ALTER TABLE items ALTER COLUMN usage_id DROP NOT NULL;
 ALTER TABLE items ADD COLUMN IF NOT EXISTS no_recipe boolean NOT NULL DEFAULT false;
+ALTER TABLE items ADD COLUMN IF NOT EXISTS image_path text NOT NULL DEFAULT '';
 ALTER TABLE items DROP COLUMN IF EXISTS no_habitat;
 
 CREATE TABLE IF NOT EXISTS recipes (
@@ -420,6 +422,7 @@ CREATE TABLE IF NOT EXISTS maps (
 CREATE TABLE IF NOT EXISTS habitats (
   id integer GENERATED BY DEFAULT AS IDENTITY PRIMARY KEY,
   name text NOT NULL UNIQUE,
+  image_path text NOT NULL DEFAULT '',
   sort_order integer NOT NULL DEFAULT 0 CHECK (sort_order >= 0)
 );
 
@@ -532,6 +535,7 @@ ALTER TABLE habitats ADD COLUMN IF NOT EXISTS updated_by_user_id integer REFEREN
 ALTER TABLE habitats ADD COLUMN IF NOT EXISTS created_at timestamptz NOT NULL DEFAULT now();
 ALTER TABLE habitats ADD COLUMN IF NOT EXISTS updated_at timestamptz NOT NULL DEFAULT now();
 ALTER TABLE habitats ADD COLUMN IF NOT EXISTS sort_order integer NOT NULL DEFAULT 0 CHECK (sort_order >= 0);
+ALTER TABLE habitats ADD COLUMN IF NOT EXISTS image_path text NOT NULL DEFAULT '';
 
 WITH ordered AS (
   SELECT id, (row_number() OVER (ORDER BY created_at, id) * 10)::integer AS next_sort_order
@@ -695,6 +699,37 @@ CREATE INDEX IF NOT EXISTS wiki_edit_logs_entity_idx
 CREATE INDEX IF NOT EXISTS wiki_edit_logs_user_id_idx
   ON wiki_edit_logs(user_id);
 
+CREATE TABLE IF NOT EXISTS entity_image_uploads (
+  id integer GENERATED BY DEFAULT AS IDENTITY PRIMARY KEY,
+  entity_type text NOT NULL CHECK (entity_type IN ('pokemon', 'items', 'habitats')),
+  entity_id integer,
+  entity_name text NOT NULL,
+  path text NOT NULL UNIQUE,
+  original_filename text NOT NULL DEFAULT '',
+  mime_type text NOT NULL CHECK (mime_type IN ('image/png', 'image/jpeg', 'image/webp', 'image/gif')),
+  byte_size integer NOT NULL CHECK (byte_size > 0),
+  created_by_user_id integer REFERENCES users(id) ON DELETE SET NULL,
+  created_at timestamptz NOT NULL DEFAULT now(),
+  CHECK (length(entity_name) BETWEEN 1 AND 120),
+  CHECK (path !~ '(^/|\\.\\.)')
+);
+
+ALTER TABLE entity_image_uploads DROP CONSTRAINT IF EXISTS entity_image_uploads_entity_type_check;
+ALTER TABLE entity_image_uploads ADD CONSTRAINT entity_image_uploads_entity_type_check CHECK (
+  entity_type IN ('pokemon', 'items', 'habitats')
+);
+
+ALTER TABLE entity_image_uploads DROP CONSTRAINT IF EXISTS entity_image_uploads_mime_type_check;
+ALTER TABLE entity_image_uploads ADD CONSTRAINT entity_image_uploads_mime_type_check CHECK (
+  mime_type IN ('image/png', 'image/jpeg', 'image/webp', 'image/gif')
+);
+
+CREATE INDEX IF NOT EXISTS entity_image_uploads_entity_idx
+  ON entity_image_uploads(entity_type, entity_id, created_at DESC, id DESC);
+
+CREATE INDEX IF NOT EXISTS entity_image_uploads_user_idx
+  ON entity_image_uploads(created_by_user_id);
+
 CREATE TABLE IF NOT EXISTS entity_discussion_comments (
   id integer GENERATED BY DEFAULT AS IDENTITY PRIMARY KEY,
   entity_type text NOT NULL CHECK (entity_type IN ('pokemon', 'items', 'recipes', 'habitats')),