feat: add CODEANY.md project guide + self-improve skill

- CODEANY.md: full architecture docs for AI-assisted development
- ~/.codeany/skills/self-improve/SKILL.md: skill for self-improvement
  Usage: /self-improve [area] — compare with Claude Code and fix gaps

Enables codeany to improve itself:
  cd ~/code/codeany && codeany "/self-improve streaming"

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: idoubi

CODEANY.md

@@ -0,0 +1,80 @@
+# CODEANY.md
+
+## Project Overview
+
+Codeany is an open-source AI-powered terminal agent, written in Go with Bubble Tea TUI. It aims to be a full-featured replacement for Claude Code with no proprietary code.
+
+## Architecture
+
+- **Runtime**: Go 1.23+, single binary
+- **TUI**: Bubble Tea + Lipgloss + Glamour (markdown)
+- **Agent SDK**: github.com/codeany-ai/open-agent-sdk-go (local dev via go.work)
+- **Build**: `go build -o codeany ./cmd/codeany/` or `make build`
+
+### Directory Structure
+
+```
+cmd/codeany/main.go           Entry point, version ldflags
+internal/
+  cli/root.go                  Cobra CLI, flags, update/upgrade
+  config/config.go             Config loading (JSON+YAML+env)
+  config/permissions.go        Permission rules persistence
+  memory/memory.go             Memory system (MEMORY.md + files)
+  pipe/pipe.go                 Non-interactive pipe mode
+  plugins/plugins.go           Plugin loading from ~/.codeany/plugins/
+  session/session.go           Session save/restore/resume
+  skills/skills.go             Skill loading from .codeany/skills/
+  slash/slash.go               Command registry + routing + autocomplete
+  slash/commands.go            All command implementations
+  team/team.go                 Team management + mailbox
+  theme/theme.go               Colors and styles
+  theme/spinners.go            Spinner verb list
+  tui/model.go                 Main Bubble Tea model (TUI core)
+  tui/input.go                 Input component (textarea + history)
+  tui/render.go                Message/tool rendering
+  version/version.go           Build-time version info
+  worktree/worktree.go         Git worktree isolation
+```
+
+### Config Directory: ~/.codeany/
+
+```
+settings.json                  Main config (model, permissions, MCP, hooks)
+config.yaml                    YAML config (alternative/legacy)
+permissions.json               Persisted permission rules
+memory/                        Memory files
+sessions/                      Session history + conversation logs
+skills/                        User skills
+plugins/                       User plugins
+teams/                         Team configs + mailboxes
+worktrees/                     Git worktree metadata
+```
+
+## Commands
+
+```bash
+# Build
+make build           # or: go build -o codeany ./cmd/codeany/
+make install         # go install with ldflags
+make vet             # go vet ./...
+make dist            # cross-compile 6 platforms
+
+# Dev
+go run ./cmd/codeany # run directly
+echo "test" | go run ./cmd/codeany -p -y  # pipe mode test
+```
+
+## Key Design Decisions
+
+- SDK at open-agent-sdk-go provides: agent loop, tools, MCP, permissions, hooks, cost tracking
+- Codeany adds: TUI, slash commands, skills, plugins, teams, sessions, config management
+- go.work used for local dev linking to SDK; go.mod uses published version for CI
+- All slash commands must be registered in BOTH AllCommands() (for autocomplete) and Handle() (for routing)
+- Permission callback in model.go is the single source of truth for tool approval
+- Hooks from config are converted to SDK HookFn functions via shell execution
+
+## Reference: Claude Code
+
+The original Claude Code is at ~/code/open-claude-code (TypeScript/Ink).
+When improving codeany, scan that codebase for feature parity.
+Key areas to compare: src/commands.ts, src/tools/, src/components/, src/screens/