add tagging system for media items

Introduces user-defined tag categories and tags with a many-to-many
relationship to media items. Tags are stored in a SQLite database
(medialore.db via better-sqlite3) with ON DELETE CASCADE for automatic
cleanup. Users can manage categories and tags at /manage/tags, assign
tags to games in the detail modal, and tag mixed media files via a
hover button on each tile.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/app/api/libraries/[id]/route.ts

@@ -1,5 +1,6 @@
 import { NextRequest, NextResponse } from 'next/server'
 import { getLibrary, removeLibrary } from '@/lib/libraries'
+import { removeAllAssignmentsForLibrary } from '@/lib/tags'
 
 export async function DELETE(
   _request: NextRequest,
@@ -13,5 +14,6 @@ export async function DELETE(
   }
 
   removeLibrary(id)
+  removeAllAssignmentsForLibrary(id)
   return new NextResponse(null, { status: 204 })
 }

src/app/api/tags/assignments/route.ts

@@ -0,0 +1,43 @@
+import { NextRequest, NextResponse } from 'next/server'
+import { getResolvedTagsForItem, addTagToItem, removeTagFromItem } from '@/lib/tags'
+
+export async function GET(request: NextRequest) {
+  try {
+    const { searchParams } = new URL(request.url)
+    const mediaKey = searchParams.get('mediaKey')
+    if (!mediaKey) {
+      return NextResponse.json({ error: 'mediaKey is required' }, { status: 400 })
+    }
+    return NextResponse.json(getResolvedTagsForItem(mediaKey))
+  } catch (err) {
+    return NextResponse.json({ error: (err as Error).message }, { status: 500 })
+  }
+}
+
+export async function POST(request: NextRequest) {
+  try {
+    const { mediaKey, tagId } = await request.json()
+    if (!mediaKey || !tagId) {
+      return NextResponse.json({ error: 'mediaKey and tagId are required' }, { status: 400 })
+    }
+    addTagToItem(mediaKey, tagId)
+    return new NextResponse(null, { status: 204 })
+  } catch (err) {
+    return NextResponse.json({ error: (err as Error).message }, { status: 400 })
+  }
+}
+
+export async function DELETE(request: NextRequest) {
+  try {
+    const { searchParams } = new URL(request.url)
+    const mediaKey = searchParams.get('mediaKey')
+    const tagId = searchParams.get('tagId')
+    if (!mediaKey || !tagId) {
+      return NextResponse.json({ error: 'mediaKey and tagId are required' }, { status: 400 })
+    }
+    removeTagFromItem(mediaKey, tagId)
+    return new NextResponse(null, { status: 204 })
+  } catch (err) {
+    return NextResponse.json({ error: (err as Error).message }, { status: 400 })
+  }
+}

src/app/api/tags/categories/[id]/route.ts

@@ -0,0 +1,44 @@
+import { NextRequest, NextResponse } from 'next/server'
+import { updateCategory, deleteCategory, deleteCategoryForce, getTags } from '@/lib/tags'
+
+export async function PATCH(
+  request: NextRequest,
+  { params }: { params: Promise<{ id: string }> }
+) {
+  try {
+    const { id } = await params
+    const { name } = await request.json()
+    const category = updateCategory(id, name)
+    return NextResponse.json(category)
+  } catch (err) {
+    return NextResponse.json({ error: (err as Error).message }, { status: 400 })
+  }
+}
+
+export async function DELETE(
+  request: NextRequest,
+  { params }: { params: Promise<{ id: string }> }
+) {
+  try {
+    const { id } = await params
+    const { searchParams } = new URL(request.url)
+    const cascade = searchParams.get('cascade') === 'true'
+
+    if (cascade) {
+      deleteCategoryForce(id)
+    } else {
+      const tags = getTags(id)
+      if (tags.length > 0) {
+        return NextResponse.json(
+          { error: `Category has ${tags.length} tag${tags.length === 1 ? '' : 's'}.`, tagCount: tags.length },
+          { status: 409 }
+        )
+      }
+      deleteCategory(id)
+    }
+
+    return new NextResponse(null, { status: 204 })
+  } catch (err) {
+    return NextResponse.json({ error: (err as Error).message }, { status: 400 })
+  }
+}

src/app/api/tags/categories/route.ts

@@ -0,0 +1,20 @@
+import { NextRequest, NextResponse } from 'next/server'
+import { getCategories, addCategory } from '@/lib/tags'
+
+export async function GET() {
+  try {
+    return NextResponse.json(getCategories())
+  } catch (err) {
+    return NextResponse.json({ error: (err as Error).message }, { status: 500 })
+  }
+}
+
+export async function POST(request: NextRequest) {
+  try {
+    const { name } = await request.json()
+    const category = addCategory(name)
+    return NextResponse.json(category, { status: 201 })
+  } catch (err) {
+    return NextResponse.json({ error: (err as Error).message }, { status: 400 })
+  }
+}

src/app/api/tags/items/[id]/route.ts

@@ -0,0 +1,29 @@
+import { NextRequest, NextResponse } from 'next/server'
+import { updateTag, deleteTag } from '@/lib/tags'
+
+export async function PATCH(
+  request: NextRequest,
+  { params }: { params: Promise<{ id: string }> }
+) {
+  try {
+    const { id } = await params
+    const { name } = await request.json()
+    const tag = updateTag(id, name)
+    return NextResponse.json(tag)
+  } catch (err) {
+    return NextResponse.json({ error: (err as Error).message }, { status: 400 })
+  }
+}
+
+export async function DELETE(
+  _request: NextRequest,
+  { params }: { params: Promise<{ id: string }> }
+) {
+  try {
+    const { id } = await params
+    deleteTag(id)
+    return new NextResponse(null, { status: 204 })
+  } catch (err) {
+    return NextResponse.json({ error: (err as Error).message }, { status: 400 })
+  }
+}

src/app/api/tags/items/route.ts

@@ -0,0 +1,22 @@
+import { NextRequest, NextResponse } from 'next/server'
+import { getTags, addTag } from '@/lib/tags'
+
+export async function GET(request: NextRequest) {
+  try {
+    const { searchParams } = new URL(request.url)
+    const categoryId = searchParams.get('categoryId') ?? undefined
+    return NextResponse.json(getTags(categoryId))
+  } catch (err) {
+    return NextResponse.json({ error: (err as Error).message }, { status: 500 })
+  }
+}
+
+export async function POST(request: NextRequest) {
+  try {
+    const { name, categoryId } = await request.json()
+    const tag = addTag(name, categoryId)
+    return NextResponse.json(tag, { status: 201 })
+  } catch (err) {
+    return NextResponse.json({ error: (err as Error).message }, { status: 400 })
+  }
+}