feat(adagents): fetch_agent_authorizations_from_directory for AAO inverse lookup (closes #746)

Adds a client function for the AAO directory's `GET /v1/agents/{agent_url}/publishers`
endpoint (adcp#4823 / #4828) — the inverse-lookup path that returns the set
of publishers whose adagents.json authorizes a given agent_url. Result is a
typed `AgentAuthorizationsDirectoryResult` (Pydantic, validated against the
real wire body). A 404 from the directory is the "not indexed" answer and
surfaces as a result with `publishers=[]`; timeouts raise
`AdagentsTimeoutError`; malformed or schema-noncompliant responses raise
`AdagentsValidationError`.

The directory's answer is *discovery*, not authorization — callers should
still verify each returned `publisher_domain` via `fetch_adagents` before
trusting the edge. Same SSRF gates apply (HTTPS only, DNS pre-check,
private/reserved address ban, 5 MiB body cap, no redirect follow).

Also bumps the schema pin to 3.1.0-beta.2 so `schemas/cache/` includes
`aao/agent-publishers.json`. Full Pydantic regen is deferred —
datamodel-code-generator mis-resolves `../enums/channels.json` when the
chain originates at a depth-0 schema (root-level `adagents.json` now
transitively references the new `core/product-format-declaration.json`,
which itself uses `../enums/...`). The hand-written models in this PR are
scoped to the new endpoint; unblocking full regen is tracked separately.

Tests use `httpx.MockTransport` to exercise the real wire shape end-to-end
and assert against `.model_validate()` on the Pydantic classes — covering
happy path, 404 → empty, `since` cursor passthrough, timeout, malformed
JSON, schema-mismatch, non-HTTPS guard, and 5xx surface.

Refs salesagent #511.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: bokelley

schemas/cache/3.1.0-beta.2/a2ui/bound-value.json

@@ -0,0 +1,80 @@
+{
+  "$schema": "http://json-schema.org/draft-07/schema#",
+  "title": "A2UI Bound Value",
+  "description": "A value that can be a literal or bound to a path in the data model",
+  "oneOf": [
+    {
+      "type": "object",
+      "description": "Literal string value",
+      "properties": {
+        "literalString": {
+          "type": "string",
+          "description": "Static string value"
+        }
+      },
+      "required": [
+        "literalString"
+      ],
+      "additionalProperties": false
+    },
+    {
+      "type": "object",
+      "description": "Literal number value",
+      "properties": {
+        "literalNumber": {
+          "type": "number",
+          "description": "Static number value"
+        }
+      },
+      "required": [
+        "literalNumber"
+      ],
+      "additionalProperties": false
+    },
+    {
+      "type": "object",
+      "description": "Literal boolean value",
+      "properties": {
+        "literalBoolean": {
+          "type": "boolean",
+          "description": "Static boolean value"
+        }
+      },
+      "required": [
+        "literalBoolean"
+      ],
+      "additionalProperties": false
+    },
+    {
+      "type": "object",
+      "description": "Path to data model value",
+      "properties": {
+        "path": {
+          "type": "string",
+          "description": "JSON pointer path to value in data model (e.g., '/products/0/title')"
+        }
+      },
+      "required": [
+        "path"
+      ],
+      "additionalProperties": false
+    },
+    {
+      "type": "object",
+      "description": "Literal with path binding (sets default and binds)",
+      "properties": {
+        "literalString": {
+          "type": "string"
+        },
+        "path": {
+          "type": "string"
+        }
+      },
+      "required": [
+        "literalString",
+        "path"
+      ],
+      "additionalProperties": false
+    }
+  ]
+}

schemas/cache/3.1.0-beta.2/a2ui/component.json

@@ -0,0 +1,31 @@
+{
+  "$schema": "http://json-schema.org/draft-07/schema#",
+  "title": "A2UI Component",
+  "description": "A component in an A2UI surface",
+  "type": "object",
+  "properties": {
+    "id": {
+      "type": "string",
+      "description": "Unique identifier for this component within the surface"
+    },
+    "parentId": {
+      "type": "string",
+      "description": "ID of the parent component (null for root)"
+    },
+    "component": {
+      "type": "object",
+      "description": "Component definition (keyed by component type)",
+      "minProperties": 1,
+      "maxProperties": 1,
+      "additionalProperties": {
+        "type": "object",
+        "description": "Component properties"
+      }
+    }
+  },
+  "required": [
+    "id",
+    "component"
+  ],
+  "additionalProperties": true
+}