Release v0.2.30: flexible navigation and clearer long-running chats

[oshtz]

Summary

• Add persisted sidebar, top-bar, and bottom-bar thread navigation with project/inbox grouping and full drag behavior.
• Improve long-running chats with reliable turn handling, latest/source affordances, unread badges, inline Mermaid, and one completed-work drawer that leaves the final answer visible.
• Polish horizontal navigation spacing, title-bar capacity, bottom-rail menus, and empty workspace-change rendering.
• Complete production-site readiness with static 404 routing, corrected headers, and docs rendering cleanup.

Verification

• git diff --check
• cargo fmt --all --check
• cargo clippy --workspace --all-targets -- -D warnings
• cargo test --workspace
• cargo clippy --manifest-path apps/desktop/src-tauri/Cargo.toml --all-targets -- -D warnings
• Tauri library tests with the Windows embedded test manifest (68 passed)
• pnpm -C apps/desktop verify:release-notes
• pnpm -C apps/desktop verify
• pnpm -C apps/site build
• pnpm -C apps/desktop verify:tauri
• pnpm -C apps/desktop test:tauri-inbox-sidebar
• pnpm -C apps/desktop test:tauri-turn-changes