docs: add Phase 3 chat architecture and overview documentation

- Add docs/kugetsu-chat.md:
  - Model B architecture (separate Chat/PM agents)
  - Session types (chat-agent, pm-agent, pm-agent-{repo}, issue sessions)
  - Hybrid message routing
  - PM Agent modes (notify/silent)
  - Context management (local + Gitea fetch on-demand)
  - Example flows

- Add docs/kugetsu.md:
  - Overview of kugetsu system
  - Quick start guide
  - Links to all documentation

- Update docs/kugetsu-architecture.md:
  - Add Phase 3 architecture section
  - Update success criteria
  - Add Phase 3 design decisions

- Add docs/telegram-setup.md:
  - BotFather bot creation guide
  - Security notes

- Remove ssh-keygen.sh (not needed)

docs/kugetsu.md

@@ -0,0 +1,111 @@
+# Kugetsu
+
+**Status:** In Development
+
+Kugetsu is an agent orchestration system that enables parallel task execution across multiple repositories through a hierarchical multi-agent architecture.
+
+## Quick Overview
+
+```
+Human (Executive)
+    └── PM Agent (Task Coordinator)
+            ├── Dev Agent A → Issue 1 → PR
+            ├── Dev Agent B → Issue 2 → PR
+            └── Dev Agent C → Issue 3 → PR
+```
+
+Your focus shifts from doing to overseeing — reviewing PRs, approving plans, managing priorities.
+
+## Core Components
+
+| Component | Implementation | Purpose |
+|-----------|---------------|---------|
+| **Session Manager** | `kugetsu` CLI | Manages opencode sessions |
+| **Chat Interface** | Hermes + Telegram | Mobile UX (Phase 3) |
+| **PM Agent** | opencode session | Task coordination |
+| **Dev Agents** | opencode sessions | Execute tasks |
+| **Communication Hub** | Gitea | Issues, PRs, Comments |
+
+## Session Architecture
+
+| Session | kugetsu ID | Purpose |
+|---------|-------------|---------|
+| Base Session | `base` | Initial TUI session for forking |
+| PM Agent | `pm-agent` | Task coordination |
+| Repo PM | `pm-agent-{repo}` | Repo-specific PM (optional) |
+| Dev Agent | `issue-{n}` | Per-issue work |
+
+## Current Capabilities
+
+### Phase 1: Remote Access ✅
+- SSH access to container
+- Tailscale VPN for cross-network access
+- See [docs/kugetsu-setup.md](kugetsu-setup.md)
+
+### Phase 2: API Interface 📋
+- Planned: REST/CLI API for task assignment
+- Status polling
+- Webhook support
+
+### Phase 3: Chat Integration 📋
+- Telegram bot for mobile UX
+- Natural language interaction
+- See [docs/kugetsu-chat.md](kugetsu-chat.md)
+
+### Phase 4: Web Dashboard 📋
+- Visual task board
+- Agent status monitoring
+- Read-only dashboards
+
+## Installation
+
+```bash
+# Clone repository
+git clone https://git.fbrns.co/shoko/kugetsu.git
+
+# Install kugetsu
+bash kugetsu/skills/kugetsu/scripts/kugetsu-install.sh
+
+# Setup SSH (optional)
+bash kugetsu/skills/kugetsu/scripts/sshd-setup.sh <username>
+
+# Setup Tailscale (optional)
+bash kugetsu/skills/kugetsu/scripts/tailscale-setup.sh <username>
+```
+
+## Quick Start
+
+```bash
+# Initialize base session (requires TTY)
+kugetsu init
+
+# Start work on issue
+kugetsu start github.com/user/repo#14 "fix bug"
+
+# Continue later
+kugetsu continue github.com/user/repo#14 "add tests"
+
+# List sessions
+kugetsu list
+```
+
+## Documentation
+
+| Document | Purpose |
+|----------|---------|
+| [kugetsu-architecture.md](kugetsu-architecture.md) | Detailed architecture |
+| [kugetsu-chat.md](kugetsu-chat.md) | Phase 3 chat design |
+| [kugetsu-setup.md](kugetsu-setup.md) | Setup guides |
+| [telegram-setup.md](telegram-setup.md) | Telegram bot setup |
+| [SUBAGENT_WORKFLOW.md](SUBAGENT_WORKFLOW.md) | Subagent execution |
+
+## Priority Model
+
+| Priority | Type |
+|----------|------|
+| 1 | Security |
+| 2 | Bugs |
+| 3 | Features |
+| 4 | Research |
+
+Within each type: Critical > High > Medium > Low