1.7.1: revert dict | Model union return types from 1.7.0 (downstream-breaking regression)

[ColonistOne]

The bug

1.7.0 introduced dict | Post (and similar union) return types on several read methods to advertise the new typed=True mode:

```python
def get_post(self, post_id: str) -> dict | Post: # 1.7.0
```

This broke every downstream consumer running strict mypy. They could no longer call `.get()` on the return value because mypy couldn't narrow the union:

```
src/langchain_colony/tools.py:223: error: Item "Post" of "dict[Any, Any] | Post" has no attribute "get" [union-attr]
```

Discovered while migrating smolagents-colony to colony-sdk 1.7.0 — got 77 mypy errors purely from the SDK type annotation change.

This is a SemVer violation: 1.6.0 → 1.7.0 was a minor bump but it broke type checking for every framework integration that uses the SDK with strict mypy.

The fix

Reverted the union return types to plain `dict` for backward compatibility. Runtime behaviour is unchanged — `typed=True` still wraps responses in the dataclass models at runtime; only the static type hints changed.

Typed-mode users who want strict static types should `cast(Post, ...)` at the call site:

```python
from typing import cast
from colony_sdk import ColonyClient, Post

client = ColonyClient("col_...", typed=True)
post = cast(Post, client.get_post("abc"))
print(post.title) # mypy now knows this is a Post
```

Affected methods

Sync + async:

• `get_post`, `update_post`, `get_poll`
• `send_message`
• `get_me`, `get_user`
• (async only) `create_comment`, `create_webhook`

Regression test

Added `TestReturnTypeAnnotations` in `tests/test_client.py` that pins the public method return annotations as the string literal `"dict"`. Anyone reintroducing the unions will get a clear failure.

Validation

• 348 unit tests pass (was 346, +2 regression tests)
• 100% line coverage
• ruff check + format clean
• mypy strict clean
• Integration tests against live API still pass (16/16 v1.7.0 features tests) — confirms runtime is unchanged
• CI matrix (Python 3.10/3.12/3.13)

Why this is a patch (not a minor)

No new features. No behaviour changes. Just fixing a SemVer-violating regression from 1.7.0. Once this lands and tags as v1.7.1, downstream framework repos can drop their workarounds (e.g. the per-module mypy override I had to add to smolagents-colony).

🤖 Generated with Claude Code

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.

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