Redesign titlebar: window title, button sizing, offline indicator

[shaunandrews]

Before

After

Summary

• Remove "Howdy, {user}" text — Gravatar-only button with tooltip showing the user's name on hover. Cleaner, less cluttered.
• Add centered window title — "Studio • {site name}" centered in the titlebar (macOS). "Studio" is dimmed/light, bullet is subtle, site name is full white. Falls back to just "Studio" when no site is selected.
• Improve titlebar button sizing — All icon buttons (sidebar toggle, gravatar, settings, help) get consistent padding (p-1.5) and rounded-lg hover states. Sidebar toggle gets extra spacing from the traffic lights.
• Reduce top/right padding — Removed redundant pt-1.5 from TopBar (chrome padding already handles it), reduced right padding so buttons sit closer to the window edge.
• Refactor offline indicator — Changed from Button to span[role=status] since it's not interactive. Removes misleading hover state while keeping tooltip and accessibility attributes. Added fill-white for SVG visibility on dark chrome.
• Add settings tooltip — Settings cog was missing a tooltip (pre-existing omission). Now shows "Settings" on hover.
• Right-align right-side tooltips — Gravatar, settings, and help tooltips use bottom-end placement so they don't overshoot the window edge.

Test plan

• macOS: Verify window title is centered between traffic lights and right controls
• macOS: Verify title updates when selecting different sites
• macOS: Verify title shows just "Studio" with no site selected
• Verify gravatar tooltip shows user display name on hover
• Verify all titlebar buttons have visible rounded hover states
• Verify offline indicator shows tooltip but no hover background (test by toggling network off)
• Verify sidebar toggle has breathing room from traffic lights
• Verify settings cog shows "Settings" tooltip on hover
• Verify right-side tooltips align to the right (bottom-end)
• Windows: Verify no regressions in Windows titlebar layout
• Unit tests pass (npm test)

🤖 Generated with Claude Code

[wpmobilebot]

📊 Performance Test Results

Comparing 2889eab vs trunk

site-editor

Metric	trunk	2889eab	Diff	Change
load	1425.00 ms	1442.00 ms	+17.00 ms	⚪ 0.0%

site-startup

Metric	trunk	2889eab	Diff	Change
siteCreation	7135.00 ms	8093.00 ms	+958.00 ms	🔴 13.4%
siteStartup	4940.00 ms	4946.00 ms	+6.00 ms	⚪ 0.0%

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Results are median values from multiple test runs.

Legend: 🟢 Improvement (faster) | 🔴 Regression (slower) | ⚪ No change (<50ms diff)