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/profile_form_templ.go

@@ -36,7 +36,7 @@ func ProfileForm(user User, actionURL string, requireCurrentPassword bool, showR
 		var templ_7745c5c3_Var2 string
 		templ_7745c5c3_Var2, templ_7745c5c3_Err = templ.ResolveAttributeValue(actionURL)
 		if templ_7745c5c3_Err != nil {
-			return templ.Error{Err: templ_7745c5c3_Err, FileName: `templates/profile_form.templ`, Line: 5, Col: 20}
+			return templ.Error{Err: templ_7745c5c3_Err, FileName: `profile_form.templ`, Line: 5, Col: 20}
 		}
 		_, templ_7745c5c3_Err = templ_7745c5c3_Buffer.WriteString(templ_7745c5c3_Var2)
 		if templ_7745c5c3_Err != nil {
@@ -57,7 +57,7 @@ func ProfileForm(user User, actionURL string, requireCurrentPassword bool, showR
 		var templ_7745c5c3_Var3 string
 		templ_7745c5c3_Var3, templ_7745c5c3_Err = templ.ResolveAttributeValue(user.Username)
 		if templ_7745c5c3_Err != nil {
-			return templ.Error{Err: templ_7745c5c3_Err, FileName: `templates/profile_form.templ`, Line: 21, Col: 27}
+			return templ.Error{Err: templ_7745c5c3_Err, FileName: `profile_form.templ`, Line: 21, Col: 27}
 		}
 		_, templ_7745c5c3_Err = templ_7745c5c3_Buffer.WriteString(templ_7745c5c3_Var3)
 		if templ_7745c5c3_Err != nil {
@@ -70,7 +70,7 @@ func ProfileForm(user User, actionURL string, requireCurrentPassword bool, showR
 		var templ_7745c5c3_Var4 string
 		templ_7745c5c3_Var4, templ_7745c5c3_Err = templ.ResolveAttributeValue(user.Email)
 		if templ_7745c5c3_Err != nil {
-			return templ.Error{Err: templ_7745c5c3_Err, FileName: `templates/profile_form.templ`, Line: 30, Col: 24}
+			return templ.Error{Err: templ_7745c5c3_Err, FileName: `profile_form.templ`, Line: 30, Col: 24}
 		}
 		_, templ_7745c5c3_Err = templ_7745c5c3_Buffer.WriteString(templ_7745c5c3_Var4)
 		if templ_7745c5c3_Err != nil {
@@ -83,7 +83,7 @@ func ProfileForm(user User, actionURL string, requireCurrentPassword bool, showR
 		var templ_7745c5c3_Var5 string
 		templ_7745c5c3_Var5, templ_7745c5c3_Err = templ.ResolveAttributeValue(user.FirstName)
 		if templ_7745c5c3_Err != nil {
-			return templ.Error{Err: templ_7745c5c3_Err, FileName: `templates/profile_form.templ`, Line: 39, Col: 28}
+			return templ.Error{Err: templ_7745c5c3_Err, FileName: `profile_form.templ`, Line: 39, Col: 28}
 		}
 		_, templ_7745c5c3_Err = templ_7745c5c3_Buffer.WriteString(templ_7745c5c3_Var5)
 		if templ_7745c5c3_Err != nil {
@@ -96,7 +96,7 @@ func ProfileForm(user User, actionURL string, requireCurrentPassword bool, showR
 		var templ_7745c5c3_Var6 string
 		templ_7745c5c3_Var6, templ_7745c5c3_Err = templ.ResolveAttributeValue(user.LastName)
 		if templ_7745c5c3_Err != nil {
-			return templ.Error{Err: templ_7745c5c3_Err, FileName: `templates/profile_form.templ`, Line: 49, Col: 27}
+			return templ.Error{Err: templ_7745c5c3_Err, FileName: `profile_form.templ`, Line: 49, Col: 27}
 		}
 		_, templ_7745c5c3_Err = templ_7745c5c3_Buffer.WriteString(templ_7745c5c3_Var6)
 		if templ_7745c5c3_Err != nil {
@@ -475,7 +475,7 @@ func ProfileForm(user User, actionURL string, requireCurrentPassword bool, showR
 			var templ_7745c5c3_Var7 string
 			templ_7745c5c3_Var7, templ_7745c5c3_Err = templ.ResolveAttributeValue("/api/auth/password/" + user.ID)
 			if templ_7745c5c3_Err != nil {
-				return templ.Error{Err: templ_7745c5c3_Err, FileName: `templates/profile_form.templ`, Line: 191, Col: 46}
+				return templ.Error{Err: templ_7745c5c3_Err, FileName: `profile_form.templ`, Line: 191, Col: 46}
 			}
 			_, templ_7745c5c3_Err = templ_7745c5c3_Buffer.WriteString(templ_7745c5c3_Var7)
 			if templ_7745c5c3_Err != nil {