Modernize provider support

CLAUDE.md

@@ -44,7 +44,7 @@ python -m cmdforge.cli  # Alternative CLI invocation
 - **runner.py**: Execution engine. Runs tool steps sequentially, handles variable substitution (`{input}`, `{varname}`), executes Python code steps via `exec()`, handles nested tool calls with depth limit (MAX_TOOL_DEPTH=10)
 - **resolver.py**: Tool resolution. `resolve_tool()` searches: project manifest → local tools → owner/name → registry. Returns `ResolvedTool` with path info
 - **collection.py**: Collection management (`Collection` dataclass, `resolve_tool_references()`, `classify_tool_reference()`), local collection storage in `~/.cmdforge/collections/`
-- **providers.py**: Provider abstraction. Calls AI CLI tools via subprocess, reads provider configs from `~/.cmdforge/providers.yaml`
+- **providers.py**: Provider abstraction. Supports subprocess CLI tools, OpenAI-compatible HTTP APIs, and experimental PTY wrappers. Auto-discovers installed providers on first run. Config in `~/.cmdforge/providers.yaml` with versioned migration.
 - **profiles.py**: AI persona profiles with system prompts, stored in `~/.cmdforge/profiles/`
 - **manifest.py**: Project manifest (`cmdforge.yaml`) for declaring tool dependencies with version constraints
 - **lockfile.py**: Lock file support for reproducible installs (`cmdforge.lock`)
@@ -100,31 +100,48 @@ Variable substitution is handled in `runner.py:substitute_variables()`. Settings
 
 ## Provider System
 
-Providers are CLI tools that accept prompts via stdin and output to stdout. Defined in `~/.cmdforge/providers.yaml`:
+Providers wrap AI CLIs or compatible HTTP APIs. Defined in `~/.cmdforge/providers.yaml`:
 
 ```yaml
+version: 2
 providers:
   - name: claude
     command: "claude -p"
     description: "Anthropic Claude"
-    fallback: claude-haiku  # Optional: try this provider if primary fails
+    type: subprocess
+  - name: openrouter
+    command: "https://openrouter.ai/api/v1"
+    description: "OpenRouter API"
+    type: api
+    model: openrouter/auto-beta
+    api_key_env: OPENROUTER_API_KEY
   - name: mock
-    command: "echo '[MOCK]'"
+    command: "mock"
+    description: "Mock provider for testing"
 ```
 
 Provider fields:
 - `name`: Provider identifier used in tool configs
-- `command`: Shell command to invoke (prompt sent via stdin)
+- `command`: Shell command (subprocess/pty) or endpoint URL (api)
+- `type`: `subprocess` (default), `api` (OpenAI-compatible HTTP), or `pty` (interactive CLI, experimental)
+- `model`: Model ID for api-type providers
+- `api_key_env`: Environment variable holding the API key for api-type providers
 - `description`: Optional human-readable description
-- `fallback`: Optional provider to try if this one fails (prevents infinite loops)
+- `fallback`: Optional provider to try if this one fails
+- `fallback_chain`: Ordered list of providers for multi-step fallback
+- `tags`: List of strings (e.g. `["free", "code", "local"]`)
+- `pty_config`: Dict with `prompt_pattern`, `response_pattern`, `exit_command` for pty providers
+- `install`: Optional structured install metadata dict
 
 The `mock` provider is built-in for testing without API calls. Use `--provider mock` or `--dry-run` flags when testing tools.
 
 Provider CLI commands:
 - `cmdforge providers list` - List all providers and their status
-- `cmdforge providers add <name> <command>` - Add/update a provider
+- `cmdforge providers check` - Check which providers are available
+- `cmdforge providers add <name> <command>` - Add/update a provider (supports `--type`, `--model`, `--api-key-env`, `--tag`, `--fallback`, `--fallback-chain`)
 - `cmdforge providers remove <name>` - Remove a provider
 - `cmdforge providers test <name>` - Test a provider
+- `cmdforge providers discover [--add]` - Scan system for installed CLIs and API keys
 - `cmdforge providers install` - Interactive guide to install AI providers
 - `cmdforge providers for-tools <tool> [tools...]` - List providers used by tools (with `--warm` to pre-load local models)