fix(templ): stop emitting literal { expr } text into attributes and body classes

templ does not interpolate { expr } inside quoted attribute values — the
braces ship as literal text (AGENTS.md gotcha #1). Swept every templ
source for the pattern and fixed all of it:

Body theme classes: 22 page bodies rendered class="theme-{ user.Theme }"
literally, so every page first-painted the :root default (Tokyo Night)
and flashed when main.js applied the real theme. All now render
class={ "theme-" + user.Theme } server-side.

Attribute interpolations (26 across 8 files):
- api_explorer: initAPIExplorerDoc path/body/response and the Copy
  Request/Response buttons (invalid JS, silently dead)
- collections: book-selection :checked/@change/@click ids and four
  hx-get search URLs (collection_id={ collection.ID })
- conflicts: Resolve button id
- devices: Kobo sync-url/auth-token element ids (copy lookups only
  worked because the id and the lookup were the same literal)
- unlinked_books: search-matches/manual-link clicks and container ids
- queue: status/priority badge classes never matched their CSS
- dashboard: Restore-section tooltip text
- collection_rules/collections: collection icon color

Free text goes through the new templates.JSONArg (json.Marshal) —
templ.JSONString in this templ version returns (string, error) and
cannot compose in attribute expressions; uuids via device.ID.String().
Includes regen-only drift from running templ generate (error-path
normalization) on files with no source change.

templates/devices.templ

@@ -13,7 +13,7 @@ templ Devices(user User, devices []handlers.DeviceInfo, pendingRegistrations []P
 			<link href="/static/style.css" rel="stylesheet"/>
 			<link rel="icon" type="image/svg+xml" href="/static/favicon.svg"/>
 		</head>
-		<body class="theme-{ user.Theme }" x-data="devices" x-init="setupEventDelegation()">
+		<body class={ "theme-" + user.Theme } x-data="devices" x-init="setupEventDelegation()">
 			@Header(user, "/devices")
 			<div class="mx-auto container px-4 sm:px-6 lg:px-8 py-8">
 				<div class="mb-8">
@@ -105,13 +105,13 @@ templ Devices(user User, devices []handlers.DeviceInfo, pendingRegistrations []P
 												<div class="flex space-x-2">
 													<input
 														type="text"
-														id="sync-url-{ device.ID }"
+														id={ "sync-url-" + device.ID.String() }
 														readonly
 														value={ baseURL + "/api/sync/kobo/" + device.AuthToken }
 														class="input text-xs font-mono"
 													/>
 													<button
-														@click="copyToClipboard(document.getElementById('sync-url-{ device.ID }').value, 'Kobo sync URL')"
+														@click={ "copyToClipboard(document.getElementById('sync-url-" + device.ID.String() + "').value, 'Kobo sync URL')" }
 														class="btn btn-primary text-xs px-3"
 													>
 														@Icon("copy", "h-4 w-4")
@@ -127,13 +127,13 @@ templ Devices(user User, devices []handlers.DeviceInfo, pendingRegistrations []P
 												<div class="flex space-x-2">
 													<input
 														type="text"
-														id="auth-token-{ device.ID }"
+														id={ "auth-token-" + device.ID.String() }
 														readonly
 														value={ device.AuthToken }
 														class="input text-xs font-mono"
 													/>
 													<button
-														@click="copyToClipboard(document.getElementById('auth-token-{ device.ID }').value, 'Auth token')"
+														@click={ "copyToClipboard(document.getElementById('auth-token-" + device.ID.String() + "').value, 'Auth token')" }
 														class="btn btn-primary text-xs px-3"
 													>
 														@Icon("copy", "h-4 w-4")