Introduce three new GStack mode profiles (gstack, code--gstack, gstack--chill) for strategic observation tracking (product decisions, demand signals, design choices). Implement a SessionManager to track mode per session, allowing all agents and the ResponseProcessor to resolve session-specific modes, and include GStack skill auto-detection.
**Type:** feature / enhancement request (re-filed from maintainer's own PR during backlog cleanup) ## Summary - **GStack mode profiles**: 3 new modes (`gstack`, `code--gstack`, `gstack--chill`) for strategic observation tracking — product decisions, demand signals, design choices - **Per-session mode overrides**: `SessionManager` tracks mode per session, all 3 agents (SDK, Gemini, OpenRouter) + ResponseProcessor resolve session-specific mode - **GStack auto-detection**: Detects GStack skill preamble in Bash commands and upgrades session mode mid-flight with observer restart - **Dynamic per-project mode via `.claude-mem.json`**: Hook reads `{ "mode": "gstack" }` from project root at session start, enabling 2+ projects to run simultaneously with different modes - **`/api/modes` endpoint**: Lists all 37 available modes for discovery by skills and UI - **`/set-mode` skill**: Creates/updates `.claude-mem.json` in the current project - **`/create-mode` skill**: Guides users through buildin