feat: foundations — canonical types, Parse grammar, env DSNs, health, chains

Phase 1 of the majordomo build:
- llm/ canonical contract (messages, parts, tools, capabilities, streaming,
  Model/Provider, error classification)
- health/ clock-injected tracker (threshold bench, exponential capped
  cooldown, reset-on-success)
- root Registry + Parse (verbatim model ids, inline recursive alias
  expansion with cycle detection, chain dedup), LLM_* env-DSN providers
  (go-llm parity: lazy fallback + eager LoadEnv), health-aware chain
  executor behind the Model interface
- provider/fake scriptable test provider; hermetic test suite incl. the
  trailing-thinking chain and foreman:// env loading
- ADRs 0001-0008, CLAUDE.md, README (honest matrix), CI workflow,
  docs/phase-1-design.md

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

.env.example

@@ -0,0 +1,16 @@
+# majordomo example environment.
+# Copy to .env and fill in real values. .env is gitignored — never commit it.
+
+# Ollama Cloud API key (used by the ollama-cloud provider and live tests).
+OLLAMA_API_KEY=your-ollama-cloud-key-here
+
+# Built-in provider keys (each optional; only needed for the providers you use).
+#OPENAI_API_KEY=sk-...
+#ANTHROPIC_API_KEY=sk-ant-...
+#GOOGLE_API_KEY=...
+
+# LLM_* env-DSN provider definitions (go-llm parity).
+# Format: LLM_<NAME>=scheme://[token@]host[/path]
+# <NAME> becomes the provider's registry name (LLM_M1 -> "m1").
+#LLM_M1=foreman://token@foreman-m1.example.com
+#LLM_M5=foreman://token@foreman-m5.example.com