…g flags (#449)

use skip-test-verification

Applies the targeted messaging API refactor from
[microsoft/teams.net#318](microsoft/teams.net#318).
The change consolidates `withTargetedRecipient()` into an enhanced
`withRecipient()` method, making targeted message creation more explicit
and reducing API surface area.

## API Changes

**Before:**
```typescript
// Implicit recipient inference
new MessageActivity('message').withTargetedRecipient(true)

// Recipient by ID only
new MessageActivity('message').withTargetedRecipient('user-123')
```

**After:**
```typescript
// Explicit recipient with targeting flag
new MessageActivity('message').withRecipient(activity.from, true)

// Full account object
new MessageActivity('message').withRecipient(
  { id: 'user-123', name: 'User', role: 'user' },
  true
)
```

## Implementation

- Moved `isTargeted` from `MessageActivity` to base `Activity` class as
non-nullable boolean (default `false`)
- Enhanced `Activity.withRecipient(account, isTargeted?)` to accept
optional targeting flag
- Removed `MessageActivity.withTargetedRecipient()` method
- Updated interface definitions to reflect property relocation
- Updated examples and tests to use new API pattern
- Updated validation error messages

## Breaking Changes

The `withTargetedRecipient()` method is removed. Callers must migrate to
`withRecipient(account, true)`.

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Co-authored-by: copilot-swe-agent[bot] <[email protected]>
Co-authored-by: rido-min <[email protected]>
Co-authored-by: Rido <[email protected]>

## Summary
Applied changes from
[microsoft/teams.net#318](microsoft/teams.net#318)
to simplify targeted messages API.

## Changes Completed
- [x] Move `is_targeted` from `_MessageBase` to base `ActivityInput`
class (as `Optional[bool] = None`)
- [x] Add `is_targeted` parameter to `ActivityInput.with_recipient()`
method (optional, only sets when specified)
- [x] Override `with_recipient()` in `MessageActivityInput` with
`is_targeted` parameter
- [x] Remove `with_targeted_recipient()` method from
`MessageActivityInput`
- [x] Remove automatic recipient inference logic from
`activity_context.py`
- [x] Add validation in `ActivityContext.send()` for targeted messages
without recipients
- [x] Update error messages to reference "account" instead of "ID"
- [x] Update unit tests to use new `with_recipient(...,
is_targeted=True)` API
- [x] Update targeted-messages example to use new API
- [x] Remove unused imports
- [x] Fix linting issues
- [x] Fix test error message regex

## API Migration
**Before:** `message.with_targeted_recipient(True)` or
`message.with_targeted_recipient("user-id")`
**After:** `message.with_recipient(account, is_targeted=True)`

## Key Design Decisions
1. **`is_targeted` is `Optional[bool] = None`**: Avoids serializing
`isTargeted: false` for all activities, preventing potential wire-format
compatibility issues with Bot Framework/Teams endpoints
2. **`with_recipient()` only sets `is_targeted` when explicitly
specified**: Prevents silently clearing the flag when just updating
recipient. Pass `is_targeted=True` to enable targeting,
`is_targeted=False` to explicitly clear it, or omit/pass `None` to leave
unchanged
3. **Validation at send time**: Clear error messages when targeted
messages lack recipients, preventing 4xx errors from the service

## Breaking Change
This is a breaking change requiring updates to all code using targeted
messages. Recipients must now be explicitly set using Account objects.

Co-authored-by: rido-min <[email protected]>

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---------

Co-authored-by: copilot-swe-agent[bot] <[email protected]>
Co-authored-by: rido-min <[email protected]>
Co-authored-by: Rido <[email protected]>
Co-authored-by: Copilot <[email protected]>
Co-authored-by: Lily Du <[email protected]>
Co-authored-by: lilydu <[email protected]>

…oft#318)

This pull request refactors how targeted messages are handled in the
Teams API SDK, consolidating targeted message logic into the
`WithRecipient` method and removing the older `WithTargetedRecipient`
methods. The changes streamline the API, improve clarity, and update
documentation and tests to reflect the new approach.

**Targeted message API refactor:**

* The `WithTargetedRecipient` methods in `MessageActivity` are removed
and replaced with an updated `WithRecipient` method that accepts an
`Account` and an optional `isTargeted` parameter. This centralizes
targeted message logic and simplifies usage.
[[1]](diffhunk://#diff-05c926d7e09179d91c9c54a68c6b5efffb854bfddb70b431df77d6b2d280c44dL221-L247)
[[2]](diffhunk://#diff-05c926d7e09179d91c9c54a68c6b5efffb854bfddb70b431df77d6b2d280c44dR149-R155)
* The `IsTargeted` property is moved from `MessageActivity` to the base
`Activity` class and is now a non-nullable `bool`, ensuring consistent
handling across activity types.
[[1]](diffhunk://#diff-875c3804dbdc89735553c417d023929c307dcfbead113a1b7a1e47871cab636aR148-R150)
[[2]](diffhunk://#diff-05c926d7e09179d91c9c54a68c6b5efffb854bfddb70b431df77d6b2d280c44dL67-L73)
* The `WithRecipient` method in both `Activity` and `MessageActivity` is
updated to support the `isTargeted` flag, replacing previous targeted
recipient APIs.
[[1]](diffhunk://#diff-875c3804dbdc89735553c417d023929c307dcfbead113a1b7a1e47871cab636aL224-R230)
[[2]](diffhunk://#diff-05c926d7e09179d91c9c54a68c6b5efffb854bfddb70b431df77d6b2d280c44dR149-R155)

**Documentation and sample updates:**

* All code samples and documentation in `Samples.TargetedMessages` are
updated to use the new `WithRecipient(..., true)` pattern instead of
`WithTargetedRecipient`.
[[1]](diffhunk://#diff-fb8b297c63493ae97cc825e8ca804ff337fbdd797c7bfda4d466fa7d87b1a78dL32-R32)
[[2]](diffhunk://#diff-fb8b297c63493ae97cc825e8ca804ff337fbdd797c7bfda4d466fa7d87b1a78dL45-R45)
[[3]](diffhunk://#diff-fb8b297c63493ae97cc825e8ca804ff337fbdd797c7bfda4d466fa7d87b1a78dL59-R59)
[[4]](diffhunk://#diff-fb8b297c63493ae97cc825e8ca804ff337fbdd797c7bfda4d466fa7d87b1a78dL81-R81)
[[5]](diffhunk://#diff-fb8b297c63493ae97cc825e8ca804ff337fbdd797c7bfda4d466fa7d87b1a78dL112-R112)
[[6]](diffhunk://#diff-75e89258d7593bb275cee67b5b18f50627f33899143d6913ae44dc5dcf9bdcdaL100-R100)
[[7]](diffhunk://#diff-75e89258d7593bb275cee67b5b18f50627f33899143d6913ae44dc5dcf9bdcdaL113-R113)
[[8]](diffhunk://#diff-75e89258d7593bb275cee67b5b18f50627f33899143d6913ae44dc5dcf9bdcdaL123-R123)

**Test suite improvements:**

* Unit tests are refactored to validate the new `WithRecipient` API for
targeted messages, replacing tests for `WithTargetedRecipient`. New
tests confirm fluent chaining and correct property assignment.
[[1]](diffhunk://#diff-9893d0b4b2ecbdda9027a251e08702b2922792adfa9f3c369674bfc6e099392aL478-R510)
[[2]](diffhunk://#diff-9893d0b4b2ecbdda9027a251e08702b2922792adfa9f3c369674bfc6e099392aR528-R543)
* The test for sending a targeted message without a recipient
proactively is removed, as the new API enforces recipient assignment.

**Validation and error handling:**

* Error messages are updated to clarify that targeted messages sent
proactively must specify an explicit recipient ID.
* Logic for inferring recipients in reactive contexts is removed, as the
new API requires explicit recipient assignment for targeted messages.

---------

Co-authored-by: Copilot <[email protected]>
Co-authored-by: rido-min <[email protected]>
Co-authored-by: Copilot <[email protected]>