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/reader_templ.go

@@ -58,7 +58,7 @@ func Reader(user User, metadata ReaderMetadata) templ.Component {
 		var templ_7745c5c3_Var2 string
 		templ_7745c5c3_Var2, templ_7745c5c3_Err = templ.JoinStringErrs(metadata.Title)
 		if templ_7745c5c3_Err != nil {
-			return templ.Error{Err: templ_7745c5c3_Err, FileName: `templates/reader.templ`, Line: 31, Col: 26}
+			return templ.Error{Err: templ_7745c5c3_Err, FileName: `reader.templ`, Line: 31, Col: 26}
 		}
 		_, templ_7745c5c3_Err = templ_7745c5c3_Buffer.WriteString(templ.EscapeString(templ_7745c5c3_Var2))
 		if templ_7745c5c3_Err != nil {
@@ -80,7 +80,7 @@ func Reader(user User, metadata ReaderMetadata) templ.Component {
 		var templ_7745c5c3_Var4 string
 		templ_7745c5c3_Var4, templ_7745c5c3_Err = templ.ResolveAttributeValue(readerInitExpr(metadata))
 		if templ_7745c5c3_Err != nil {
-			return templ.Error{Err: templ_7745c5c3_Err, FileName: `templates/reader.templ`, Line: 41, Col: 36}
+			return templ.Error{Err: templ_7745c5c3_Err, FileName: `reader.templ`, Line: 41, Col: 36}
 		}
 		_, templ_7745c5c3_Err = templ_7745c5c3_Buffer.WriteString(templ_7745c5c3_Var4)
 		if templ_7745c5c3_Err != nil {
@@ -93,7 +93,7 @@ func Reader(user User, metadata ReaderMetadata) templ.Component {
 		var templ_7745c5c3_Var5 string
 		templ_7745c5c3_Var5, templ_7745c5c3_Err = templ.ResolveAttributeValue(templ.CSSClasses(templ_7745c5c3_Var3).String())
 		if templ_7745c5c3_Err != nil {
-			return templ.Error{Err: templ_7745c5c3_Err, FileName: `templates/reader.templ`, Line: 1, Col: 0}
+			return templ.Error{Err: templ_7745c5c3_Err, FileName: `reader.templ`, Line: 1, Col: 0}
 		}
 		_, templ_7745c5c3_Err = templ_7745c5c3_Buffer.WriteString(templ_7745c5c3_Var5)
 		if templ_7745c5c3_Err != nil {
@@ -175,7 +175,7 @@ func ReaderChrome(metadata ReaderMetadata) templ.Component {
 		var templ_7745c5c3_Var7 templ.SafeURL
 		templ_7745c5c3_Var7, templ_7745c5c3_Err = templ.JoinURLErrs("/media/" + metadata.MediaItemID)
 		if templ_7745c5c3_Err != nil {
-			return templ.Error{Err: templ_7745c5c3_Err, FileName: `templates/reader.templ`, Line: 308, Col: 63}
+			return templ.Error{Err: templ_7745c5c3_Err, FileName: `reader.templ`, Line: 308, Col: 63}
 		}
 		_, templ_7745c5c3_Err = templ_7745c5c3_Buffer.WriteString(templ.EscapeString(templ_7745c5c3_Var7))
 		if templ_7745c5c3_Err != nil {
@@ -188,7 +188,7 @@ func ReaderChrome(metadata ReaderMetadata) templ.Component {
 		var templ_7745c5c3_Var8 string
 		templ_7745c5c3_Var8, templ_7745c5c3_Err = templ.JoinStringErrs(metadata.Title)
 		if templ_7745c5c3_Err != nil {
-			return templ.Error{Err: templ_7745c5c3_Err, FileName: `templates/reader.templ`, Line: 311, Col: 95}
+			return templ.Error{Err: templ_7745c5c3_Err, FileName: `reader.templ`, Line: 311, Col: 95}
 		}
 		_, templ_7745c5c3_Err = templ_7745c5c3_Buffer.WriteString(templ.EscapeString(templ_7745c5c3_Var8))
 		if templ_7745c5c3_Err != nil {
@@ -230,7 +230,7 @@ func drawerHeader(title string) templ.Component {
 		var templ_7745c5c3_Var10 string
 		templ_7745c5c3_Var10, templ_7745c5c3_Err = templ.JoinStringErrs(title)
 		if templ_7745c5c3_Err != nil {
-			return templ.Error{Err: templ_7745c5c3_Err, FileName: `templates/reader.templ`, Line: 580, Col: 35}
+			return templ.Error{Err: templ_7745c5c3_Err, FileName: `reader.templ`, Line: 580, Col: 35}
 		}
 		_, templ_7745c5c3_Err = templ_7745c5c3_Buffer.WriteString(templ.EscapeString(templ_7745c5c3_Var10))
 		if templ_7745c5c3_Err != nil {