feat(05-04): extend Tier 1 provider verify specs

- 12 Tier 1 providers now carry success_codes, failure_codes, rate_limit_codes
- {{KEY}} template in headers or URL (double-brace canonical form)
- metadata_paths added where provider APIs return useful metadata
- Anthropic switched to POST /v1/messages with minimal body
- Perplexity gains JSON body, content-type header
- Inflection verify URL left empty (no public endpoint)
- Dual-location sync preserved: providers/ mirrors pkg/providers/definitions/

pkg/providers/definitions/anthropic.yaml

@@ -15,10 +15,16 @@ patterns:
     entropy_min: 3.5
     confidence: high
 verify:
-  method: GET
-  url: https://api.anthropic.com/v1/models
+  method: POST
+  url: https://api.anthropic.com/v1/messages
   headers:
-    x-api-key: "{KEY}"
+    x-api-key: "{{KEY}}"
     anthropic-version: "2023-06-01"
-  valid_status: [200]
-  invalid_status: [401, 403]
+    content-type: "application/json"
+  body: '{"model":"claude-haiku-4-5","max_tokens":1,"messages":[{"role":"user","content":"hi"}]}'
+  success_codes: [200]
+  failure_codes: [401, 403]
+  rate_limit_codes: [429, 529]
+  metadata_paths:
+    model: "model"
+    stop_reason: "stop_reason"