fix: Correct Alpine.js directive syntax in 4 template files

Fixed templ parsing errors caused by escaped quotes in Alpine.js @click
directives. The previous migration to @click used backslash-escaped
quotes (\") which templ cannot parse correctly.

Files affected:
- templates/api_explorer.templ:28 - Fixed missing <button> tag and quotes
- templates/collection_modal.templ:69,135 - Fixed color picker buttons (edit & create forms)
- templates/collections.templ:216 - Fixed remove book button
- templates/conflicts.templ:110 - Fixed resolve conflict button

Root cause: Commit 08d4561 converted onclick→@click but used escaped quotes
Fix: Replace all @click=\"function()\" with @click="function()"

This aligns with the standard Alpine.js pattern and fixes the 4 templ
generation errors reported in ESBUILD_MIGRATION_PLAN.md line 1168.

Resolves: Template parsing errors preventing build
Related: ESBUILD_MIGRATION_PLAN.md Phase 3 (Template Migration)

templates/conflicts.templ

@@ -107,9 +107,9 @@ templ Conflicts(user User, conflicts []handlers.ConflictDetailResponse, total in
 										<p class="text-sm" style="color: var(--text-secondary)">Type: { conflict.ConflictType }</p>
 									</div>
 								</div>
-								<button @click=\"showConflictModal('{ conflict.ID }')\" class="btn-primary px-4 py-2 rounded-lg">
-									Resolve
-								</button>
+							<button @click="showConflictModal('{ conflict.ID }')" class="btn-primary px-4 py-2 rounded-lg">
+								Resolve
+							</button>
 							</div>
 							<div class="text-sm" style="color: var(--text-secondary)">
 								Created: { conflict.CreatedAt.Format("2006-01-02 15:04:05") }