feat(ift): EventHub AI Router stack for Zed

FastAPI gateway with A/B/C lane orchestration, LiteLLM proxy config,
Swarm stack (postgres, redis, VPN off-by-default), deploy/smoke/audit scripts.

config/model_matrix.yaml

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+# tier × lane (A/B/C) → Novita model id + LiteLLM fallbacks
+
+lanes:
+  A: economy
+  B: balanced
+  C: max
+
+models:
+  a-simple:
+    novita: novita/qwen/qwen3-4b-fp8
+    fallbacks: [b-simple, groq-llama-8b]
+    rpm: 60
+  b-simple:
+    novita: novita/meta-llama/llama-3.1-8b-instruct
+    fallbacks: [a-simple, groq-llama-8b]
+    rpm: 60
+  c-simple:
+    novita: novita/qwen/qwen3-8b-fp8
+    fallbacks: [b-simple]
+    rpm: 60
+
+  a-medium-ops:
+    novita: novita/qwen/qwen3-8b-fp8
+    fallbacks: [a-medium-code, b-medium-ops]
+    rpm: 40
+  b-medium-ops:
+    novita: novita/deepseek/deepseek-v3.2
+    fallbacks: [a-medium-code, c-medium-ops]
+    rpm: 40
+  c-medium-ops:
+    novita: novita/deepseek/deepseek-v3.2
+    fallbacks: [b-medium-ops]
+    rpm: 40
+
+  a-medium-code:
+    novita: novita/qwen/qwen3-coder-30b-a3b-instruct
+    fallbacks: [a-medium-ops, groq-qwen-coder]
+    rpm: 40
+  b-medium-code:
+    novita: novita/qwen/qwen3-coder-30b-a3b-instruct
+    fallbacks: [b-medium-ops, c-medium-code]
+    rpm: 40
+  c-medium-code:
+    novita: novita/qwen/qwen3-coder-30b-a3b-instruct
+    fallbacks: [b-medium-code, c-medium-ops]
+    rpm: 30
+
+  a-complex:
+    novita: novita/deepseek/deepseek-v3.2
+    fallbacks: [b-complex, a-reasoning]
+    rpm: 30
+  b-complex:
+    novita: novita/deepseek/deepseek-r1-0528
+    fallbacks: [a-complex, c-complex]
+    rpm: 20
+  c-complex:
+    novita: novita/deepseek/deepseek-r1-turbo
+    fallbacks: [b-complex]
+    rpm: 15
+
+  a-reasoning:
+    novita: novita/deepseek/deepseek-r1-0528-qwen3-8b
+    fallbacks: [b-reasoning, gemini-flash]
+    rpm: 30
+  b-reasoning:
+    novita: novita/deepseek/deepseek-r1-0528
+    fallbacks: [a-reasoning, c-reasoning]
+    rpm: 20
+  c-reasoning:
+    novita: novita/deepseek/deepseek-r1-turbo
+    fallbacks: [b-reasoning, gemini-flash]
+    rpm: 15
+
+  a-vision-ocr:
+    novita: novita/paddlepaddle/paddleocr-vl
+    fallbacks: [a-vision]
+    rpm: 30
+    no_escalation: true
+  a-vision:
+    novita: novita/qwen/qwen3-vl-30b-a3b-instruct
+    fallbacks: [a-vision-ocr]
+    rpm: 20
+  b-vision:
+    novita: novita/qwen/qwen2.5-vl-72b-instruct
+    fallbacks: [a-vision, c-vision]
+    rpm: 15
+  c-vision:
+    novita: novita/qwen/qwen3-vl-235b-a22b-instruct
+    fallbacks: [b-vision]
+    rpm: 10
+
+optional_providers:
+  groq-llama-8b:
+    model: groq/llama-3.1-8b-instant
+    api_key: os.environ/GROQ_API_KEY
+  groq-qwen-coder:
+    model: groq/qwen-qwen-2.5-coder-32b
+    api_key: os.environ/GROQ_API_KEY
+  gemini-flash:
+    model: gemini/gemini-2.0-flash
+    api_key: os.environ/GEMINI_API_KEY
+
+audit:
+  price_drift_threshold_pct: 10
+  cheaper_alternative_pct: 15

config/orchestration.yaml

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+default_quality_mode: auto
+
+start_lanes:
+  SIMPLE: A
+  MEDIUM_OPS: A
+  MEDIUM_CODE: A
+  COMPLEX: B
+  REASONING: B
+  VISION_OCR: A
+  VISION_UI: A
+
+quality_mode_map:
+  economy: A
+  balanced: B
+  max: C
+
+lane_order: [A, B, C]
+
+budget_caps:
+  warn_pct: 80
+  hard_pct: 95
+  warn_max_lane: B
+  hard_max_lane: A
+
+escalation:
+  repeat_prompt_window_sec: 300
+  context_tokens_min_lane_b: 32000
+  session_ttl_sec: 1800
+
+redis:
+  key_prefix: "ai-router:session:"
+  ttl_sec: 1800

config/routing_rules.yaml

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+# Tier classification — single source for gateway + LiteLLM keyword rules
+
+gateway:
+  simple_patterns:
+    - "^(привет|hello|hi|hey|спасибо|thanks|что такое|what is|define)\\b"
+  complex_keywords:
+    - рефакторинг
+    - refactor
+    - архитектур
+    - architecture
+    - спроектируй
+    - design system
+    - microservice
+    - distributed
+    - migration plan
+    - deep refactor
+  reasoning_keywords:
+    - step by step
+    - prove
+    - analyze deeply
+    - think through
+    - reasoning
+  medium_ops_keywords:
+    - bash
+    - docker
+    - swarm
+    - ci/cd
+    - gitea
+    - rebar
+    - erlang
+    - devops
+    - kubectl
+    - terraform
+    - playwright
+    - npm
+    - wsl
+    - litellm
+    - novita
+    - traefik
+    - mnesia
+  ocr_keywords:
+    - ocr
+    - прочитай текст
+    - extract text
+    - распознай текст
+    - read text from
+  escalation_keywords:
+    - не подходит
+    - лучше
+    - качественнее
+    - retry
+    - попробуй ещё
+  word_thresholds:
+    simple_max_words: 12
+    simple_question_max_words: 25
+    complex_min_words: 400
+    medium_code_min_lines: 200
+  confidence:
+    low_threshold: 0.6
+
+litellm:
+  keyword_tier_rules:
+    - keywords: ["привет", "hello", "hi", "thanks", "спасибо", "что такое", "what is", "define"]
+      tier: SIMPLE
+    - keywords: ["bash", "docker", "swarm", "ci/cd", "gitea", "rebar", "erlang", "devops", "kubectl", "terraform", "playwright", "npm", "wsl"]
+      tier: MEDIUM
+    - keywords: ["рефакторинг", "refactor", "архитектура", "architecture", "спроектируй", "design system", "microservice", "distributed", "migration plan"]
+      tier: COMPLEX
+    - keywords: ["step by step", "reasoning", "prove", "analyze deeply", "think through"]
+      tier: REASONING
+  custom_technical_keywords:
+    - erlang
+    - rebar3
+    - traefik
+    - mnesia
+    - litellm
+    - novita