feat(update): show an update icon in the view header when a newer release is out

[luoxuanzao]

Summary

• When GitHub has a newer stable release than the installed plugin, an update icon appears in the view header next to the feedback and settings buttons; clicking it opens Qoderian's plugin page inside Obsidian (via obsidian://show-plugin?id=…), where Obsidian's own update button lives — no trip to the browser.
• The version check asks the GitHub releases API once per plugin session (/releases/latest → tag_name), compares it segment-by-segment with the installed manifest.version, and stays silent on any failure (offline, rate limit, malformed payload) so update discovery never blocks chat.
• The icon is a normal header action button (brand-colored download icon, tooltip carries the version) and sets height/padding/border/background through a doubled class so the theme's default button chrome cannot take it over.

Verification

• npm run typecheck
• npm run lint
• npm run test — 165 suites / 3555 tests pass
• npm run build
• npm run release:check — Release 1.0.11 is ready
• npm run audit:prod — 0 vulnerabilities
• Real-app check in a live vault: the icon only appears when the installed manifest is older than the latest release (verified by lowering the dev vault's manifest against the current release); it renders 16×16 like its sibling icons, the tooltip reads "Update 1.0.11", and clicking opens the plugin page — repeated clicks keep working after opening and closing that page

Safety

• No credentials, private vault content, internal URLs, or personal paths are included
• User-visible changes are documented in CHANGELOG.md

Co-authored-by: QoderAI (Qwen 3.8 Max) qoder_ai@qoder.com