Move message history out of core (#21278)

## Why

Message history was implemented inside `codex-core` and surfaced through
core protocol ops and `SessionConfiguredEvent` fields even though the
current consumer is TUI-local prompt recall. That made core own UI
history persistence and exposed `history_log_id` / `history_entry_count`
through surfaces that app-server and other clients do not need.

This change moves message history persistence out of core and keeps the
recall plumbing local to the TUI.

## What changed

- Added a new `codex-message-history` crate for appending, looking up,
trimming, and reading metadata from `history.jsonl`.
- Removed core protocol history ops/events: `AddToHistory`,
`GetHistoryEntryRequest`, and `GetHistoryEntryResponse`.
- Removed `history_log_id` and `history_entry_count` from
`SessionConfiguredEvent` and updated exec/MCP/test fixtures accordingly.
- Updated the TUI to dispatch local app events for message-history
append/lookup and keep its persistent-history metadata in TUI session
state.

## Validation

- `cargo test -p codex-message-history -p codex-protocol`
- `cargo test -p codex-exec event_processor_with_json_output`
- `cargo test -p codex-mcp-server outgoing_message`
- `cargo test -p codex-tui`
- `just fix -p codex-message-history -p codex-protocol -p codex-core -p
codex-tui -p codex-exec -p codex-mcp-server`

codex-rs/Cargo.lock

@@ -3132,6 +3132,19 @@ dependencies = [
  "wiremock",
 ]
 
+[[package]]
+name = "codex-message-history"
+version = "0.0.0"
+dependencies = [
+ "codex-config",
+ "pretty_assertions",
+ "serde",
+ "serde_json",
+ "tempfile",
+ "tokio",
+ "tracing",
+]
+
 [[package]]
 name = "codex-model-provider"
 version = "0.0.0"
@@ -3674,6 +3687,7 @@ dependencies = [
  "codex-install-context",
  "codex-login",
  "codex-mcp",
+ "codex-message-history",
  "codex-model-provider",
  "codex-model-provider-info",
  "codex-models-manager",