OpenSquilla 0.5.5: C5 fusion and persistent workspaces

🦐 OpenSquilla 0.5.5 introduces C5 multi-model fusion, more reliable tasks, persistent workspaces, Tencent SkillHub, and signed Windows installers, while improving chats, Plans, Goals, models, Skills, and Desktop recovery.

🧠 C5 fusion — four models draft responses in parallel, then a tool-capable model combines them into one final answer.

💬 Chats, Plans, and Goals — reconnect recovery is more reliable, attachment drafts are saved, task progress can be edited, and pause, resume, and cancellation states are clearer.

🗂️ Workspaces and documents — task files persist across sessions, HTML can be previewed locally, files gain inline actions, and document reading and editing use bounded operations.

🧩 Models and Skills — model limits are editable, Router presets account for the selected provider, Tencent SkillHub is supported, and managed commands can accept interactive terminal input.

🖥️ Desktop — startup is faster, Gateway recovery is stronger, and the Windows installer is now Authenticode signed.

Upgrading from 0.5.4: quit Desktop and the Gateway, back up the active profile, and install over the existing version. Configuration, chats, Agents, memory, and schedules stay in place, supported database migrations run automatically, and clients and Gateway should be upgraded together.

Migration notes: the one-time Router version 2 migration replaces C0–C3 text tiers and saves a timestamped config backup; reapply custom tiers afterward. Goal Token budgets and foreground/background execution settings are retired, as are older bundled Skills, format-specific authoring tools, and workspace BOOTSTRAP.md, HEARTBEAT.md, and TOOLS.md integration. Move required workspace instructions into AGENTS.md.