Bundled Bangla fonts, macOS-style icons, native layout tab, Chromium cursor fixes, and build cleanups

[Zibonnn]

Summary

Design-driven changes to how Lekho looks and renders Bangla, plus correctness and size fixes that fell out along the way. 13 commits ahead of main, no divergence.

Icons (design)

• New app icon in the macOS style: rounded squircle, layered depth, sized for Dock and Finder at every slot.
• New menu-bar icon drawn to match the native "EN" input source glyph, so switching between English and Lekho looks like one system. It inverts correctly on dark menu bars.

Fonts and rendering (design)

• Bundled July and BCC Purno under fonts/, shipped in the app via ATSApplicationFontsPath, so the candidate panel and welcome window render Bangla in July regardless of what the user has installed. Both are open-source fonts released by the Government of Bangladesh.
• Installed system-wide on launch. A background task copies the bundled fonts into ~/Library/Fonts so every app can use them. An existing copy is replaced only when the bundled one is newer; /Library/Fonts is never touched. The uninstaller offers to remove them.
• NSFont.withBangla(_:) builds one font whose cascade falls through to July (July-Bold for semibold and up) for Bengali. Latin, digits and emoji keep the system font, so mixed candidates line up.

Welcome window (design)

• Native Avro layout tab. LayoutWebView and the WebKit dependency are gone. The layout is ~70 AppKit cards grouped by section with a live search field.
• Vowel cards show the vowel sign (আ / া, ই / ি) instead of a ক-based example.
• Phala and reph cards show their marks. A zero-width joiner next to the hasanta makes the shaper emit the standalone subjoined form, so ব-ফলা, য-ফলা, র-ফলা and রেফ display the real glyph rather than hasanta plus consonant.
• Special section corrected against the engine. Backtick is a pattern separator (it emits nothing), not ZWJ. Tilde and .. have no Avro rule, so the ZWNJ and nukta cards are dropped.
• Shortcut table replaces the row-by-row list; shared cardHeader and scrollingPage helpers keep the tabs consistent.
• Tabs build lazily on first selection.

Input controller

• Chromium cursor position. Chromium ignores selectionRange.location for a collapsed selection and puts the caret at 0. For Chromium clients we pass {0, N} (caret lands at the end), set markedClauseSegment, and anchor the panel from selectedRange() with a marked-range fallback.
• Chromium detection by framework bundle instead of a bundle-id substring list. Every Chromium/Electron app ships a <Name> Framework.framework, which catches Arc (company.thebrowser.Browser) and Cursor (com.todesktop.<hash>). Cached per bundle id.
• Candidates extracted once per keystroke and reused by the panel and candidates(_:), instead of three walks over riti's list.
• Remembered selection index 0 is treated as "nothing remembered", since riti returns 0 for both cases. Without this, phonetic-first stopped applying once a word had been seen.
• Ctrl+Backspace reaches riti for whole-word delete instead of being passed through.
• UInt8(clamping:) on the selected index instead of a trapping conversion.

Candidate panel

• Clicking the bottom padding strip no longer selects the next, hidden row.

Build, scripts, CI

• Release binary is stripped (~400 KB smaller).
• Icon generator renders into an explicit 8-bit rep; tiffRepresentation produced 16-bit slices and a 2.2 MB icns. Now 900 KB.
• create_dmg.sh reads the version from Info.plist for the DMG name, pkgbuild, and distribution XML.
• uninstall.sh uses rm -rf on the /Applications entry, which may be a symlink or a real copy.
• Homebrew bump workflow passes tag values through env: and targets ${{ github.repository_owner }}/homebrew-lekho, which resolves to your tap here.

Notes for review

• Version bumped to 0.2.7 in Info.plist. Adjust as you like.
• Not tested on Intel.

🤖 Generated with Claude Code

[ARahim3]

Hi @Zibonnn, that's a lot of careful work, and I read all of it. Thank you.

I can't take it as one PR though. It changes icons, fonts, the layout tab, the input controller and the build scripts together, and the input controller was rewritten for v0.3.0 in the meantime, so it no longer applies. For the design side (icons, bundled fonts, the native layout tab) I'd like to talk before any code, one topic per issue.

Several bugs you caught are fixed in v0.3.0, and you're credited in the release notes: the remembered-selection 0 problem that broke Phonetic-first, the trapping UInt8 conversion, whole-word delete (Option+Backspace), and the click below the last row of the panel.

The Chromium caret one I'd like to look at properly. Could you open an issue with the app and steps to reproduce?