Python: bump package versions for 1.2.2 release (#5561)

* Python: bump package versions for 1.2.2 release

PATCH bump (1.2.1 -> 1.2.2) for the released cohort. Five PRs land in this
window:

- agent-framework-openai: fix file_search citations breaking the assistant-
  message history roundtrip (#5557) — drives the released-tier PATCH
- agent-framework-orchestrations: [BREAKING] standardize orchestration
  terminal outputs as AgentResponse (#5301)
- agent-framework-core, agent-framework-declarative: preserve Workflow.run()
  shared state across calls, accept list[Message] in declarative start
  executor, and coerce Enum values when serializing PowerFx symbols (#5531)
- agent-framework-foundry-hosting: add hosted Durable Workflow support
  (#5531)
- agent-framework-azure-contentunderstanding: new alpha package — Azure AI
  Content Understanding context provider (#4829)
- dependencies: workspace package dependency refresh (#5555)

Per lockstep convention, all 21 beta packages stamp 1.0.0b260429 and all 4
alpha packages (now including the new contentunderstanding) stamp
1.0.0a260429. Date stamp reflects 2026-04-29 Pacific. Every non-core package
floor on agent-framework-core is raised to >=1.2.2; the new
contentunderstanding package's stale >=1.0.0 floor is brought into line.

Two follow-on fixes bundled to keep validate-dependency-bounds-test green
at lowest-direct resolution:
- Bump agent-framework-azure-contentunderstanding's azure-ai-content
  understanding lower bound from >=1.0.0 to >=1.0.1 (1.0.0 ships without
  proper typing — pyright reports 65 unknown-type errors)
- Add pyright ignore comments to core/foundry/__init__.pyi for the new
  alpha package's type-stub imports, since alpha packages are not in
  core's [all] extra and therefore aren't installed at lowest-direct

* Python: add #5552 to 1.2.2 CHANGELOG

Add the streaming-span observability fix to the Fixed section. PR is on
upstream/main but not yet pulled into origin/main; the code itself will
land via the PR merge.

* Python: address PR #5561 review feedback on dependency bounds

Two packaging fixes flagged in review:

1. agent-framework-azure-contentunderstanding: add agent-framework-foundry
   as a runtime dependency. The package's README directs users to
   `pip install agent-framework-azure-contentunderstanding --pre` and the
   basic example imports `FoundryChatClient` from `agent_framework.foundry`,
   so the documented install path was failing with ImportError. Pulling
   agent-framework-foundry into deps makes the advertised entry path
   self-contained.

2. agent-framework-foundry: bump agent-framework-openai lower bound from
   >=1.1.0 to >=1.2.2,<2. Foundry imports private modules from
   agent_framework_openai (`_chat_client.py:22`, `_agent.py:34`), so
   resolvers were free to pair foundry==1.2.2 with older OpenAI versions
   that lack this release's coordinated Responses/history fix. Lockstep the
   floor with the released cohort to prevent mismatched installs.

Both changes pass `validate-dependency-bounds-test` lower + upper at
their respective packages.

python/packages/azure-contentunderstanding/samples/02-devui/01-multimodal_agent/agent.py

@@ -21,13 +21,11 @@ Run with DevUI:
 import os
 
 from agent_framework import Agent
-from agent_framework.foundry import FoundryChatClient
+from agent_framework.foundry import ContentUnderstandingContextProvider, FoundryChatClient
 from azure.core.credentials import AzureKeyCredential
 from azure.identity import AzureCliCredential
 from dotenv import load_dotenv
 
-from agent_framework.foundry import ContentUnderstandingContextProvider
-
 load_dotenv()
 
 # --- Auth ---

python/packages/azure-contentunderstanding/samples/02-devui/02-file_search_agent/foundry_backend/agent.py

@@ -32,17 +32,16 @@ Run with DevUI:
 import os
 
 from agent_framework import Agent
-from agent_framework.foundry import FoundryChatClient
+from agent_framework.foundry import (
+    ContentUnderstandingContextProvider,
+    FileSearchConfig,
+    FoundryChatClient,
+)
 from azure.core.credentials import AzureKeyCredential
 from azure.identity import AzureCliCredential
 from dotenv import load_dotenv
 from openai import AzureOpenAI
 
-from agent_framework.foundry import (
-    ContentUnderstandingContextProvider,
-    FileSearchConfig,
-)
-
 load_dotenv()
 
 # --- Auth ---