Rename TMDB_API_KEY to TMDB_API_READ_ACCESS_TOKEN and add optional base URL overrides

Renames the env var for clarity since it holds a read access token, not an API
key. Adds optional TMDB_API_BASE_URL and TMDB_IMAGE_BASE_URL env vars for
advanced users. Centralizes image URL construction into a shared tmdbImageUrl()
helper, replacing hardcoded URLs across all components.

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

components/command-palette.tsx

@@ -8,6 +8,7 @@ import {
   IconSearch,
 } from "@tabler/icons-react";
 import Image from "next/image";
+import { tmdbImageUrl } from "@/lib/tmdb/image";
 import { useRouter } from "next/navigation";
 import { useCallback, useEffect, useState } from "react";
 import { useKeyboard } from "@/components/keyboard-provider";
@@ -211,7 +212,7 @@ export function CommandPalette() {
                     <div className="h-12 w-8 shrink-0 overflow-hidden rounded bg-muted">
                       {r.posterPath ? (
                         <Image
-                          src={`https://image.tmdb.org/t/p/w92${r.posterPath}`}
+                          src={tmdbImageUrl(r.posterPath, "w92")!}
                           alt={r.title}
                           width={32}
                           height={48}

components/search-autocomplete.tsx

@@ -7,6 +7,7 @@ import { useRouter } from "next/navigation";
 import { useCallback, useEffect, useRef, useState } from "react";
 import { toast } from "sonner";
 import { useDebounce } from "@/hooks/use-debounce";
+import { tmdbImageUrl } from "@/lib/tmdb/image";
 
 interface SearchResult {
   tmdbId: number;
@@ -165,7 +166,7 @@ export function SearchAutocomplete({
                   <div className="h-[60px] w-10 shrink-0 overflow-hidden rounded-md bg-muted">
                     {r.posterPath ? (
                       <Image
-                        src={`https://image.tmdb.org/t/p/w92${r.posterPath}`}
+                        src={tmdbImageUrl(r.posterPath, "w92")!}
                         alt={r.title}
                         width={40}
                         height={60}

components/title-card.tsx

@@ -3,6 +3,7 @@
 import { motion } from "motion/react";
 import Image from "next/image";
 import Link from "next/link";
+import { tmdbImageUrl } from "@/lib/tmdb/image";
 
 interface TitleCardProps {
   id?: string;
@@ -27,9 +28,7 @@ export function TitleCard({
   onImport,
 }: TitleCardProps) {
   const year = releaseDate?.slice(0, 4);
-  const posterUrl = posterPath
-    ? `https://image.tmdb.org/t/p/w300${posterPath}`
-    : null;
+  const posterUrl = tmdbImageUrl(posterPath, "w300");
 
   const content = (
     <motion.div