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/collection_modal_templ.go

@@ -72,7 +72,7 @@ func CollectionModal(collection CollectionData) templ.Component {
 			var templ_7745c5c3_Var2 string
 			templ_7745c5c3_Var2, templ_7745c5c3_Err = templ.ResolveAttributeValue("/api/collections/" + collection.ID)
 			if templ_7745c5c3_Err != nil {
-				return templ.Error{Err: templ_7745c5c3_Err, FileName: `templates/collection_modal.templ`, Line: 23, Col: 49}
+				return templ.Error{Err: templ_7745c5c3_Err, FileName: `collection_modal.templ`, Line: 23, Col: 49}
 			}
 			_, templ_7745c5c3_Err = templ_7745c5c3_Buffer.WriteString(templ_7745c5c3_Var2)
 			if templ_7745c5c3_Err != nil {
@@ -85,7 +85,7 @@ func CollectionModal(collection CollectionData) templ.Component {
 			var templ_7745c5c3_Var3 string
 			templ_7745c5c3_Var3, templ_7745c5c3_Err = templ.ResolveAttributeValue(collection.ID)
 			if templ_7745c5c3_Err != nil {
-				return templ.Error{Err: templ_7745c5c3_Err, FileName: `templates/collection_modal.templ`, Line: 26, Col: 57}
+				return templ.Error{Err: templ_7745c5c3_Err, FileName: `collection_modal.templ`, Line: 26, Col: 57}
 			}
 			_, templ_7745c5c3_Err = templ_7745c5c3_Buffer.WriteString(templ_7745c5c3_Var3)
 			if templ_7745c5c3_Err != nil {
@@ -98,7 +98,7 @@ func CollectionModal(collection CollectionData) templ.Component {
 			var templ_7745c5c3_Var4 string
 			templ_7745c5c3_Var4, templ_7745c5c3_Err = templ.ResolveAttributeValue(collection.Name)
 			if templ_7745c5c3_Err != nil {
-				return templ.Error{Err: templ_7745c5c3_Err, FileName: `templates/collection_modal.templ`, Line: 32, Col: 30}
+				return templ.Error{Err: templ_7745c5c3_Err, FileName: `collection_modal.templ`, Line: 32, Col: 30}
 			}
 			_, templ_7745c5c3_Err = templ_7745c5c3_Buffer.WriteString(templ_7745c5c3_Var4)
 			if templ_7745c5c3_Err != nil {
@@ -111,7 +111,7 @@ func CollectionModal(collection CollectionData) templ.Component {
 			var templ_7745c5c3_Var5 string
 			templ_7745c5c3_Var5, templ_7745c5c3_Err = templ.JoinStringErrs(collection.Description)
 			if templ_7745c5c3_Err != nil {
-				return templ.Error{Err: templ_7745c5c3_Err, FileName: `templates/collection_modal.templ`, Line: 45, Col: 31}
+				return templ.Error{Err: templ_7745c5c3_Err, FileName: `collection_modal.templ`, Line: 45, Col: 31}
 			}
 			_, templ_7745c5c3_Err = templ_7745c5c3_Buffer.WriteString(templ.EscapeString(templ_7745c5c3_Var5))
 			if templ_7745c5c3_Err != nil {
@@ -124,7 +124,7 @@ func CollectionModal(collection CollectionData) templ.Component {
 			var templ_7745c5c3_Var6 string
 			templ_7745c5c3_Var6, templ_7745c5c3_Err = templ.ResolveAttributeValue(collection.Icon)
 			if templ_7745c5c3_Err != nil {
-				return templ.Error{Err: templ_7745c5c3_Err, FileName: `templates/collection_modal.templ`, Line: 58, Col: 83}
+				return templ.Error{Err: templ_7745c5c3_Err, FileName: `collection_modal.templ`, Line: 58, Col: 83}
 			}
 			_, templ_7745c5c3_Err = templ_7745c5c3_Buffer.WriteString(templ_7745c5c3_Var6)
 			if templ_7745c5c3_Err != nil {
@@ -137,7 +137,7 @@ func CollectionModal(collection CollectionData) templ.Component {
 			var templ_7745c5c3_Var7 string
 			templ_7745c5c3_Var7, templ_7745c5c3_Err = templ.ResolveAttributeValue(collection.Color)
 			if templ_7745c5c3_Err != nil {
-				return templ.Error{Err: templ_7745c5c3_Err, FileName: `templates/collection_modal.templ`, Line: 74, Col: 86}
+				return templ.Error{Err: templ_7745c5c3_Err, FileName: `collection_modal.templ`, Line: 74, Col: 86}
 			}
 			_, templ_7745c5c3_Err = templ_7745c5c3_Buffer.WriteString(templ_7745c5c3_Var7)
 			if templ_7745c5c3_Err != nil {
@@ -155,7 +155,7 @@ func CollectionModal(collection CollectionData) templ.Component {
 			var templ_7745c5c3_Var8 string
 			templ_7745c5c3_Var8, templ_7745c5c3_Err = templ.ResolveAttributeValue(collection.Icon)
 			if templ_7745c5c3_Err != nil {
-				return templ.Error{Err: templ_7745c5c3_Err, FileName: `templates/collection_modal.templ`, Line: 135, Col: 83}
+				return templ.Error{Err: templ_7745c5c3_Err, FileName: `collection_modal.templ`, Line: 135, Col: 83}
 			}
 			_, templ_7745c5c3_Err = templ_7745c5c3_Buffer.WriteString(templ_7745c5c3_Var8)
 			if templ_7745c5c3_Err != nil {