feat(app): template library with 100+ i18n templates, response language selector and extension fixes

[Refaltor77]

Summary

✨ Template Library (100+ templates) ─

• Added a full template library accessible from the sidebar via a Templates button (BookOpen icon)
• Library opens as a modal overlay (not a tab) to avoid cluttering the app layout
• 100+ templates across 10 categories: Writing, Code, Marketing, Productivity, Design, Education, Sales, Data, Creative, Personal
• Each template pre-fills the canvas with typed, structured blocks ready to edit
• Category filter bar to browse templates by type

🌍 Multilingual templates + response language selector

• Template names and descriptions are locale-aware: display adapts to the user's selected language (EN/FR with English fallback for other locales)
• Added a "Response language" dropdown in the library overlay: selecting a language automatically appends a language block to the loaded template nodes
• LOCALE_TO_LANG mapping covers 16 languages (EN, FR, ES, DE, IT, PT, ZH, JA, KO, AR, RU, NL, PL, SV, TR, HI)
• Updated all 10 locale JSON files (en, fr, es, de, pt, ja, tr, zh, ar, ru) with the new library i18n section

🧱 Block pills redesign (Sidebar)

• Sidebar block pills now show a description line that fades in on hover, making each block type self-explanatory without cluttering the UI
• Tooltips were intentionally kept off the canvas nodes (only in the sidebar list)

🧩 Extension fixes (to check if this was intentional or not)

• Fixed auto-import: prompt text is now automatically sent to the iframe when the sidebar opens (no need to click "Import from ChatGPT" manually)
• Fixed platform auto-detection: FLOMPT_PLATFORM_INFO is re-sent every time the sidebar opens, so the correct AI tab (ChatGPT / Claude / Gemini) is pre-selected
• Fixed iframe load sequence: input text is sent on load if already available
• DEV_MODE reset to false before commit (was left true during local development)

Files changed

• app/src/lib/templates.ts — new file, 100+ templates with i18n structure
• app/src/components/TemplateLibrary.tsx — full rewrite with locale-aware display + language selector
• app/src/components/Sidebar.tsx — Templates button + block pill description redesign
• app/src/App.tsx — library as modal overlay, removed library tab
• app/src/store/flowStore.ts — Tab type kept compatible
• app/src/i18n/en.json + fr.json — library section added (translated)
• app/src/i18n/*.json (×8) — library section added (English fallback)
• app/src/i18n/translations.ts — library interface added
• app/src/styles.css — library overlay, template grid, language selector, block pill styles

[Nyrok]

Amazing!

[Nyrok]

To make template contribution easier, maybe we should move the templates in a specific folder, with a template per file.
With a convention on the template structure: It can be a .json file or something else.
To be discussed!

[Nyrok]

However, it can be implemented later. I'm merging it.

[Refaltor77]

think the best approach is to set up a database so that we can easily use it in the future

[Nyrok]

Definitely