feat: add adapter base class and project roadmap

Add PulseAdapter abstract base class — the foundation for the adapter
ecosystem (v0.6.0). Adapters bridge PULSE messages to external APIs,
enabling "write once, work with any service" pattern.

Features:
- Abstract base class with send/to_native/call_api/from_native pipeline
- HTTP error code → PULSE error concept mapping
- Health check with request/error tracking
- Standardized error response creation
- Action support declaration and checking
- Connection lifecycle management (connect/disconnect)

Also:
- Add ROADMAP.md with v0.6.0-v1.0.0 development plan
- Fix pyproject.toml version (0.4.0 → 0.5.0) and GitHub URLs
- 28 new adapter tests (total: 284 tests, all passing)
- Export PulseAdapter, AdapterError, AdapterConnectionError from pulse package

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: Sergey Klein

ROADMAP.md

@@ -0,0 +1,163 @@
+# PULSE Protocol — Roadmap
+
+## Current: v0.5.0 (Alpha)
+
+**Completed:**
+- Core message system (3-layer architecture)
+- JSON encoding (human-readable)
+- Binary encoding (MessagePack, 10x compression)
+- Compact encoding (13x compression)
+- Vocabulary system (1,000 concepts, 10 categories)
+- 3-stage message validation
+- HMAC-SHA256 signing & verification
+- Replay protection (timestamp + nonce)
+- TLS transport layer (HTTPS client/server)
+- CLI tool (6 commands)
+- 256+ tests, 90%+ coverage
+- 8 working examples
+
+---
+
+## Next: v0.6.0 — Adapters (The Bridge Phase)
+
+**Goal:** Make PULSE useful TODAY, before anyone adopts it natively.
+
+Adapters translate PULSE messages into existing APIs. Your bot speaks PULSE, the adapter translates. The target service doesn't even know PULSE exists.
+
+```
+Your bot → PULSE message → Adapter → Target API
+Target API → Response → Adapter → PULSE message → Your bot
+```
+
+### Priority Adapters
+
+| Adapter | Package | What it does |
+|---------|---------|-------------|
+| **OpenAI** | `pulse-openai` | Talk to GPT models via PULSE messages |
+| **Anthropic** | `pulse-anthropic` | Talk to Claude via PULSE messages |
+| **Binance** | `pulse-binance` | Trade on Binance via PULSE messages |
+| **Slack** | `pulse-slack` | Send/receive Slack messages via PULSE |
+| **GitHub** | `pulse-github` | Interact with GitHub API via PULSE |
+
+### How Adapters Work
+
+```python
+from pulse import PulseMessage
+from pulse_openai import OpenAIAdapter
+
+adapter = OpenAIAdapter(api_key="sk-...")
+
+# Your bot speaks PULSE — adapter translates to OpenAI API
+request = PulseMessage(
+    action="ACT.ANALYZE.SENTIMENT",
+    target="ENT.DATA.TEXT",
+    parameters={"text": "Bitcoin is going to the moon!"}
+)
+
+# Adapter converts PULSE → OpenAI API call → PULSE response
+response = adapter.send(request)
+# response.content["result"]["sentiment"] == "PROP.SENTIMENT.POSITIVE"
+```
+
+### Switching providers = one line change
+
+```python
+# Today: OpenAI
+from pulse_openai import OpenAIAdapter
+adapter = OpenAIAdapter(api_key="sk-...")
+
+# Tomorrow: Anthropic (same bot code, different adapter)
+from pulse_anthropic import AnthropicAdapter
+adapter = AnthropicAdapter(api_key="sk-ant-...")
+
+# Same request works with both:
+response = adapter.send(request)
+```
+
+### Adapter Architecture
+
+Every adapter implements the same interface:
+
+```python
+class PulseAdapter:
+    """Base adapter interface."""
+
+    def send(self, message: PulseMessage) -> PulseMessage:
+        """Send PULSE message, get PULSE response."""
+        native_request = self.to_native(message)     # PULSE → API format
+        native_response = self.call_api(native_request)  # Call target API
+        return self.from_native(native_response)     # API format → PULSE
+
+    def to_native(self, message: PulseMessage) -> dict:
+        """Convert PULSE message to target API format."""
+        ...
+
+    def from_native(self, response: dict) -> PulseMessage:
+        """Convert target API response to PULSE message."""
+        ...
+```
+
+---
+
+## v0.7.0 — Multi-Agent Framework
+
+**Goal:** Enable multiple PULSE agents to work together.
+
+- Agent registry (discover other agents)
+- Message routing (send to the right agent)
+- Workflow orchestration (chain agents together)
+- Load balancing (distribute work across agents)
+
+---
+
+## v0.8.0 — PULSE Transactions
+
+**Goal:** Economic layer for autonomous AI agents.
+
+- Transaction vocabulary (`ACT.TRANSACT.*`, `PROP.COST.*`, `ENT.RESOURCE.*`)
+- Transaction lifecycle (request → offer → accept → settle)
+- Cryptographic settlement (signed, verified, auditable)
+- See: [pulse-transactions/](../pulse-transactions/)
+
+---
+
+## v1.0.0 — Production Release
+
+**Goal:** Production-ready protocol for enterprise and community use.
+
+- Stable API (no breaking changes after v1.0)
+- PyPI publication (`pip install pulse-protocol`)
+- Complete documentation
+- Security audit
+- Performance optimization
+- Framework integrations (LangChain, CrewAI, AutoGen)
+
+---
+
+## Future
+
+- **Rust implementation** — High-performance, embedded systems
+- **Go implementation** — Cloud-native, microservices
+- **JavaScript/TypeScript** — Browser and Node.js
+- **Native adoption** — Platforms support PULSE directly (no adapters needed)
+- **IETF RFC** — Submit PULSE as an internet standard
+
+---
+
+## Adoption Strategy
+
+### Phase 1: Adapters (v0.6.0)
+Developers use PULSE between their own agents. Adapters translate to existing APIs. No one else needs to change anything.
+
+### Phase 2: Community (v0.7.0-v0.8.0)
+Multi-agent frameworks and transaction support attract more developers. Open-source adapters grow organically.
+
+### Phase 3: Native Adoption (v1.0+)
+When enough bots use PULSE, platforms adopt it natively. Adapters become unnecessary. Full speed, full compression, full benefit.
+
+**This is exactly how HTTP, TCP/IP, and USB became standards — bottom-up adoption, not top-down mandate.**
+
+---
+
+*Created by Sergej Klein*
+*License: Apache 2.0 — free forever*

pulse/__init__.py

@@ -14,6 +14,7 @@
 from pulse.client import PulseClient
 from pulse.server import PulseServer
 from pulse.tls import TLSConfig, generate_self_signed_cert
+from pulse.adapter import PulseAdapter, AdapterError, AdapterConnectionError
 from pulse.exceptions import (
     PulseException,
     ValidationError,
@@ -41,6 +42,9 @@
     "PulseServer",
     "TLSConfig",
     "generate_self_signed_cert",
+    "PulseAdapter",
+    "AdapterError",
+    "AdapterConnectionError",
     "PulseException",
     "ValidationError",
     "EncodingError",