Feat(remote) workspace session UI

[bobleer]

Summary

Improves remote SSH workspace handling (paths, caps, workspace state), desktop/session/agentic APIs, and the web UI for SSH auth, flow chat sessions, and nav/workspace integration. Documentation updates clarify Windows OpenSSL bootstrap when using pnpm vs plain cargo.

Motivation

• Remote workspaces need consistent path resolution and SSH-related workspace state so the desktop agent and UI stay aligned with the actual remote root.
• SSH flows benefit from a dedicated auth prompt instead of a password-only dialog.
• Flow chat and session layers need tighter wiring to persistence and session APIs for a stable experience across workspace switches.

What changed

Core & desktop (feat(core,desktop): …)

• path_manager and remote_ssh / workspace_state for remote roots and capability handling.
• Workspace service/manager integration for remote scenarios.
• Tauri-side updates: agentic_api, app_state, commands, session_api, terminal_api, etc.
• Agentic: coordinator, session, persistence, session_manager adjustments as needed for the above.

Web UI & docs (feat(web-ui): …)

• SSH: SSHAuthPromptDialog (replaces PasswordInputDialog), updates to SSHConnectionDialog, SSHRemoteProvider, pathUtils, file-system hooks/services, editor/git panels where paths cross the boundary.
• Flow chat: FlowChatManager, SessionModule, PersistenceModule, BtwThreadService, FlowChatStore, types and tool-card/theme-related styling.
• Nav / layout: sessions section, workspace item, AppLayout, input/preview CSS tweaks.
• APIs: AgentAPI, SessionAPI.
• README / README.zh-CN: Windows OpenSSL — no manual ZIP; pnpm run desktop:* vs node scripts/ensure-openssl-windows.mjs when using plain cargo.

How to test

1. Desktop: Open a local workspace, then connect/use a remote SSH workspace; confirm roots, file tree, and agent actions use the expected paths.
2. SSH auth: Trigger auth flows; confirm the new prompt behaves correctly for your auth method.
3. Flow chat: Create/switch sessions and workspaces; confirm threads persist and reload as expected.
4. Windows dev: Follow README OpenSSL section for both pnpm run desktop:dev and optional plain cargo workflow.

Notes

• Branch is based on current main from this repo (includes recent upstream commits such as AI connection test alignment).
• Split into two commits for easier review: backend first, then web-ui + docs.