design new updating ux and log download flow

[Douglasymlai]

Closes #1433

Related Issue

Closes #

Description

This PR redesigns the desktop app update experience and expands the Support dialog with dedicated log downloads.

Top bar update UX

• Replaces the old toast-based update flow (src/components/update/index.tsx) with a new inline UpdateButton in the top bar.
• When an update is available, the app auto-starts a background download once per session, then shows an inline progress bar with percentage.
• After download completes, the button changes to Launch new version (calls quit-and-install).
• Download failures surface as an inline retry affordance instead of error toasts.
• Adds a dev-only debug-update-event IPC handler so the update UI can be exercised from DevTools in unpackaged builds.

Support dialog & log downloads

• Renames the dialog to Support, with Report a bug as a subsection.
• Adds a Download logs section with two export actions:
  • Eigent log — existing desktop app logs (export-log)
  • Camel log — CAMEL backend task logs (export-camel-log), targeting the active task when available and falling back to all camel_logs directories under the user's identity roots
• New Electron plumbing: getCamelLogEntries, zipDirectories, findDirectoriesByName, preload bridge, and typed exportCamelLog API.

Other fixes

• Renders the Sonner toaster into document.body via a portal so toasts are no longer trapped below dialog overlays by #root's stacking context.
• Adds i18n strings for the new update and support-log copy.
• Extends ReportBugDialog unit tests for Eigent/Camel log download flows (5 tests passing).

Testing Evidence (REQUIRED)

Automated tests

npm test -- test/unit/components/Dialog/ReportBugDialog.test.tsx
# ✓ 5 tests passed

Manual verification

• Top bar shows inline download progress when an update is available, then Launch new version after completion.
• Support dialog → Download exports Eigent log to a user-chosen path with a success toast.
• Support dialog → Download exports Camel log for the active task (or all camel_logs when no task is active).
• Toasts appear above the Support dialog (portal fix).
• (Attach screenshot/screen recording of top-bar update states and Support dialog log section.)

[] I have included human-verified testing evidence in this PR.
[] This PR includes frontend/UI changes, and I attached screenshot(s) or screen recording(s).
[x] No frontend/UI changes in this PR.

What is the purpose of this pull request?

• Bug fix
• New Feature
• Documentation update
• Other

Contribution Guidelines Acknowledgement

• I have read and agree to the Eigent Contribution Guideline

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