feat: add taskbar strip side and offset controls

[ElliotDrel]

The taskbar strip is fixed beside the notification area, so users cannot use the empty space on the left of a centered taskbar. This adds Left / Right placement and an Offset (px) control under Settings → Taskbar strip.

• Left anchors to the taskbar's left edge; Right anchors beside the notification area (or secondary clock).
• The offset moves inward, scales with each monitor's DPI, and is saved with the existing strip settings. Existing installations keep Right with an 8 px offset.
• Coordinates are clamped to the taskbar area before the tray. A strip too wide to fit is hidden. This does not reserve space for Start, Widgets or app buttons; users can adjust the offset to avoid them.
• Includes all 11 UI translations, an updated translation lock, documentation, and regression tests for settings persistence, keyboard editing, input validation, DPI scaling and bounds. Temporary empty/invalid offset text stays local to the input; only valid numbers are saved, and blur restores the last valid number.

Validation:

• Production frontend build and TypeScript check passed.
• Full frontend/provider suite passed: 73 files, 1,287 tests (bun run test --run --pool=threads --maxWorkers=2). The default fork worker mode stalled locally; thread workers completed successfully.
• Windows verification passed the production frontend build, cargo test --locked --lib (212 passed, 1 ignored), and cargo build --locked --bins for b6465b4. Native source is unchanged since that run; the subsequent offset-input fix was verified by a fresh frontend build and test suite. The fork-only verification workflow is not part of this PR.
• Screenshots omitted at the requester's direction. Live taskbar behavior has not been manually verified.

[chatgpt-codex-connector]

Codex Review Summary

This comment shows the latest Codex review activity on this pull request.

Review	Status	Commit	Review trigger
📝 Code Review	✅ Completed 2026-10-15T16:33:09.124565Z	b6465b4	Draft marked ready

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