mentra 0.28.0 / mentra-provider 0.9.0

Removed the RegisteredProvider alias

• Breaking: mentra_provider::RegisteredProvider is removed. It was a bare
  pub use Provider as RegisteredProvider; with no callers outside the crate's
  own provider impls; use Provider.

Folded ModelCatalog and ProviderSessionFactory into Provider

• Breaking: the ModelCatalog and ProviderSessionFactory traits are
  removed; list_models and create_session are now required methods on
  Provider itself. Every implementor in the workspace already implemented all
  three traits on the same type, and neither trait was ever used as a dyn type
  or a generic bound. External implementors merge their two impl blocks into
  their Provider impl.

Removed the unread RetryPolicy provider config

• Breaking: mentra::RetryPolicy / mentra_provider::RetryPolicy and the
  ProviderDefinition::retry field are removed. No code in the workspace ever
  read the policy; per-run retry behavior is configured with
  RunOptions::provider_retry (mentra::runtime::ProviderRetry) and is
  unchanged. Serialized ProviderDefinition JSON carrying a retry key still
  deserializes (the key is ignored).

Removed two unused OAuth credential-source constructors

• Breaking (feature openai-oauth):
  OpenAIOAuthCredentialSource::from_default_persistent_store and
  ::from_default_persistent_store_or_authorize are removed. Both were
  one-line defaults with no callers; pass PersistentTokenStoreKind::Auto to
  from_persistent_store / from_persistent_store_or_authorize for the
  identical behavior.

Removed the test-only MemoryTokenStore

• Breaking (feature openai-oauth): mentra::auth::openai::MemoryTokenStore
  is removed. Nothing in the crate constructed it outside its own unit test; the
  in-memory store now lives in that test module. The TokenStore trait stays
  public, so an in-memory store is a few lines to write.

Removed the duplicate provider::model re-export module

• Breaking: mentra::provider::model is removed. Every item it re-exported
  is already re-exported one level up at mentra::provider::* (and at
  mentra::provider_core::*); import from there instead.

Builtin providers are constructor functions, not forwarding types

• Breaking: the seven forwarding wrapper types in mentra::provider are
  removed: openai::OpenAIProvider, openrouter::OpenRouterProvider,
  anthropic::AnthropicProvider, gemini::GeminiProvider,
  openai_compatible::OpenAiCompatibleProvider, ollama::OllamaProvider and
  lmstudio::LmStudioProvider. Each held a single Arc<dyn Provider> and
  forwarded every trait method to it verbatim.
• Free functions returning Arc<dyn Provider> replace them, with the same
  arguments and the same resulting descriptor and capabilities:
  openai::provider, openai::with_credential_source,
  openai::with_shared_credential_source, openrouter::provider,
  anthropic::provider, gemini::provider, openai_compatible::new,
  openai_compatible::without_credentials, ollama::provider,
  ollama::with_base_url, lmstudio::provider, lmstudio::with_base_url.
• Provider is now implemented for Arc<dyn Provider>, so the results go
  straight into RuntimeBuilder::with_provider_instance and
  Runtime::register_provider_instance as before.
• Behavior change (Anthropic, Gemini): the removed AnthropicProvider and
  GeminiProvider wrappers did not forward compact, so provider-native
  history compaction always failed with UnsupportedCapability and the
  compaction engine silently fell back to local summarization even though both
  providers advertise supports_history_compaction. Without the wrappers the
  compact call now reaches the real provider, so runtimes built with
  with_anthropic / with_gemini compact remotely under
  CompactionMode::PreferRemote and report CompactionExecutionMode::Remote
  where they previously reported Local. Set CompactionMode::LocalOnly (the default) to keep
  the old behavior.

Agent state no longer carries an empty compaction key

• The always-empty CompactionState placeholder is gone from
  AgentMemoryState and from the state.json / SQLite state payload. Agent
  state written by older versions still loads; state written now cannot be
  read by an older build.

Removed the unused SearchRequest conversion struct

• Breaking: mentra::memory::SearchRequest is removed. Nothing
  constructed it; every caller builds a MemorySearchRequest directly.
• MemoryEngine::search now takes MemorySearchRequest by value instead of
  impl Into<MemorySearchRequest>.

Removed the never-read MemorySearchRequest::mode knob

• Breaking: mentra::memory::MemorySearchMode and the
  MemorySearchRequest::mode field are removed. No MemoryStore
  implementation ever branched on the value, so search results are unchanged.

Removed unreachable McpServerStatus variants

• Breaking: McpServerStatus::Disconnected and ::Connecting are removed
  from the mentra::McpServerStatus re-export. Nothing ever constructed them:
  list_servers reports Connected for a live server and Error for a name
  that only failed to connect, and a disconnected server is dropped from the
  listing rather than reported. Out-of-repo match arms on those variants must
  be deleted.

MCP clients share one dispatch mechanism

• McpBridgedTool::new is no longer generic over the transport; it takes
  Arc<dyn McpToolClient>. Call sites passing a concrete Arc<McpStdioClient>
  or Arc<McpSseClient> are unaffected, because the Arc coerces at the
  argument position.
• The sealed McpToolClient trait gains a shutdown method, replacing the
  manager's private transport enum. The trait is sealed, so no out-of-crate
  implementor exists to update.

Resumed sessions can opt into a different runtime namespace

• SessionResumeOptions::runtime_identifier lets a host rehome a legacy or
  renamed-workspace session on its next persist. None keeps the stored tag;
  Some(id) replaces it for that resumed session without retagging other
  agents or changing the shared runtime's identifier
  (#59).
• Source-breaking: exhaustive SessionResumeOptions struct literals must
  add runtime_identifier: None or use ..Default::default().

Removed unused PermissionRequest type

• Source-breaking: the public mentra::PermissionRequest struct is removed.
  Nothing produced or consumed it; the live path is the
  SessionEvent::PermissionRequested variant and its inline fields.

Removed duplicate SubagentHandle::task_id

• Source-breaking: SubagentHandle::task_id is removed. It always held the
  same value as agent_id, which is the identifier reported as the task_id
  of the subagent's SessionEvent::TaskUpdated events.

Removed unused CancellationFlag alias

• Source-breaking: the mentra::runtime::CancellationFlag type alias is
  removed; use mentra::runtime::CancellationToken, which it aliased.

Removed unused compaction type aliases

• Source-breaking: the mentra::agent aliases ContextCompactionConfig,
  ContextCompactionTrigger and ContextCompactionDetails are removed; use
  CompactionConfig, CompactionTrigger and CompactionDetails. The persisted
  context_compaction field name keeps working through its serde alias.