Settings: db-viewer redesign, theme/accent wiring, macOS overlay titlebar (#6)

* feat: settings back button returns to origin view (push/pop nav)

* feat: redesign settings screen with db-viewer border styling

* fix: settings sidebar — icon+text tabs, back at top, top border (PR feedback)

* fix: tighten settings sidebar — back and tabs in one group

* fix: settings header shows active tab name instead of duplicated title

* fix: settings — accent back button, header shows active tab; fix App test

* fix: tags settings — no create label, no card chrome (bg/border/padding)

* feat: drag-and-drop tag reordering in settings tags tab

* fix: general settings — remove section card chrome (bg/border/padding)

* fix: merge Appearance and Interface into one settings section

* fix: remove row separators between settings items within sections

* fix: settings rows use gap spacing instead of per-row padding

* feat: strip section cards from all settings tabs; delete SettingsSection

* feat: apply theme and font size settings (appearance wiring)

* feat: honor default folder setting on startup

* feat: confirm_before_delete setting now skips delete confirmations

* feat: default_ports setting prefills new connection forms

* fix: light theme — text colors, native window chrome, ThemePicker preview

* fix: sync window background color with theme so title bar follows light mode

* fix: window-sync test uses microtask flush instead of vi.waitFor

* fix: app root carries canvas bg so home-screen parent matches theme

* fix: grant window set-theme/set-background-color permissions so title bar follows theme

* fix: overlay title bar — webview paints under traffic lights, flat canvas color in both themes

* fix: compact 28px overlay titlebar with visible bottom border

* fix: in-flow titlebar strip (draggable via allowed permission); screens fill remaining height, no bottom clipping

* fix: top border only on settings + db viewer pages, not the titlebar strip

* fix: db viewer sidebar h-screen -> h-full (28px overflow clipped bottom icons)

* fix: system theme resets window to OS before reading matchMedia (was polluted by forced window theme)

* fix: theme switcher labels moved below previews for readability

* feat: configurable accent color setting (circle palette in Appearance)

* docs: update AGENTS.md + README for settings redesign, wired settings, accent color

README.md

@@ -238,6 +238,7 @@ gridline/
 - **Home Screen Filters** — Tag filter with OR semantics, folder cards matching tags or containing matching connections, DB type filter hiding empty folders, environment filter (All/Production/Staging/Development/None), global search across all folders with "Showing Search Results" breadcrumb + Clear
 - **Query History & Saved Queries** — toolbar history dropdown (load / run / favorite / clear), favorites, consecutive-identical dedup + 500-retention pruning, SaveQueryDialog, and a two-pane Queries view (History / Saved Queries sidebar scoped per connection + tabbed query workspace)
 - **Consolidated Navigation** — merged Functions/Triggers/Sequences/Enums/Extensions into a single Objects view (object-type dropdown) and Backup/Restore/DB Sync into a single Tools view (operation dropdown)
+- **Settings (Redesigned & Fully Wired)** — DB-viewer-styled settings screen (icon+text sidebar, tab-titled header, border-sharp no-card sections, Back returns to origin view); all settings functional: theme (light/dark/system, applied live + native macOS Overlay titlebar sync), font size, **accent color** (circle palette), default folder on startup, confirm-before-delete toggle, default ports prefill; drag-and-drop tag reorder
 
 ### 🟡 In Progress / Upcoming
 - **Editor Settings** — font, tab size, word wrap, minimap options