fix(search): restore lazy-loaded search bar

[Smana]

Problem

The site search was completely broken. The lazy-load rework in 8f554ae ("perf: lazy-load search bundle") introduced three bugs in layouts/partials/search/scripts.html:

1. Double-encoded asset URLs. {{ … | jsonify }} inside a <script> block double-encodes, because Hugo's html/template already JS-escapes values in that context. src/integrity ended up wrapped in literal quotes ("\"http://…\""), so the bundle URL was malformed → 404 → the script never loaded.
2. Init never fired. search.js self-initializes on the window load event, but the bundle is now injected on first focus/input — after load has already fired — so its handler never ran. Typing did nothing.
3. Dedicated /search/ page broke. It renders results from the ?query= URL param via passiveSearch, which needs the bundle on page load, not on focus. Deep-links (search submit, result clicks) showed no results.

Fix

• Drop the redundant jsonify — let Hugo's context-aware escaping produce clean JS strings.
• Kick off init from the script's onload (guarded by readyState === 'complete'), and replay the current input value since the listener attaches late.
• Eager-load the bundle on the /search/ page (detected via #searchpage); keep lazy-loading everywhere else, preserving the original perf goal.

Verification

Driven end-to-end in headless Chromium against a production build (cold cache):

Flow	Result
Live search (focus + type) — EN home, FR home, EN post list	✅ 8 results each
Search page deep-link — /search/?query=, /fr/search/?query=	✅ 12 results each

The ~30 KB fuse+search bundle still only downloads when the user intends to search (or lands on the search page).