feat: improve terminal UX with links, WebGL fix, search toggles, keyboard remaps, and word selection

[sonSunnoi]

Summary

• Link detection: register UrlLinkProvider + FilePathLinkProvider — Cmd/Ctrl+click opens URLs and file paths
• WebGL race fix: move activatePreferredTerminalRenderer after terminal.open() so WebGL has a DOM parent
• Search toggles: add case-sensitive and regex toggle buttons to find bar; persist preferences across searches
• Addons: load Unicode11Addon (before open) and LigaturesAddon (after renderer activation)
• macOS keyboard remaps: Cmd+Backspace → kill line, Cmd+Left/Right → line nav, Option+Left/Right → word nav, Option+Backspace → kill word
• Word selection: Option+Shift+Left/Right extends visual selection by word via buffer scan + terminal.select()
• Test suite: add registerLinkProvider no-op stub to all MockTerminal classes; fix ligatures Vite alias resolution

Test plan

• Cmd/Ctrl+click on a URL in terminal opens browser
• Cmd/Ctrl+click on a file path opens file
• WebGL renderer activates without console errors on first open
• Find bar case-sensitive toggle filters results correctly
• Find bar regex toggle enables regex search
• Search preferences persist when toggling find bar closed and reopening
• Cmd+Backspace deletes to start of line
• Option+Left/Right moves cursor by word
• Option+Backspace deletes previous word
• Option+Shift+Left/Right extends selection by word
• Unit tests pass: pnpm test

🤖 Generated with Claude Code

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