Thread context.Context through blocking I/O entry points

Accept ctx as the first parameter on the blocking I/O entry points and
propagate it to downstream blocking calls so the work is cancellable from
the process entry point:

- appconfig.Load / LoadWithOptions: honor ctx before the blocking file
  reads, returning defaults on a cancelled context.
- LSP: lsp.Server.Run(ctx) ties the serve loop to the caller context via a
  new watchParentContext bridge (cancels the server context, aborting
  in-flight LLM work). Threaded through hexailsp.Run/RunWithConfig/
  RunWithFactory and runtimeconfig.Store.Reload.
- MCP: mcp.Server.Run(ctx) stops accepting requests once ctx is cancelled;
  threaded through hexaimcp.Run/RunWithFactory/RunBackfill.
- editor: RunEditor/OpenTempAndEdit/OpenFile take ctx and use
  exec.CommandContext so a cancelled context kills the editor subprocess;
  threaded through hexaicli, hexaiaction and askcli call sites.

Top-level callers (cmd/hexai-lsp-server, cmd/hexai-mcp-server) now build a
signal-cancelled context (SIGINT/SIGTERM) so shutdown tears the run down
cleanly. Updated comments to explain the cancellation flow and added
cancellation tests for the LSP/MCP loops, editor, and config load.

All tests pass with -race; cross-package coverage 86.2%.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

1 files changed, 4 insertions, 4 deletions

diff --git a/internal/hexaiaction/run_more_test.go b/internal/hexaiaction/run_more_test.go
index 67ffa96..97bcbe9 100644
--- a/internal/hexaiaction/run_more_test.go
+++ b/internal/hexaiaction/run_more_test.go
@@ -31,7 +31,7 @@ func TestRun_MissingAPIKey(t *testing.T) {
 
 func TestRun_NoInput_IsActionable(t *testing.T) {
 	runner := NewRunner()
-	runner.loadConfig = func(context.Context, *log.Logger) appconfig.App { return appconfig.Load(nil) }
+	runner.loadConfig = func(context.Context, *log.Logger) appconfig.App { return appconfig.Load(context.Background(), nil) }
 	runner.newClient = func(appconfig.App) (actionClient, error) { return llmFake{}, nil }
 	runner.chooseAction = func(appconfig.App) (actionChoice, error) {
 		return actionChoice{kind: ActionSkip}, nil
@@ -62,7 +62,7 @@ func TestHandleDiagnosticsActionInvokesLLM(t *testing.T) {
 	t.Setenv("HEXAI_TMUX_STATUS", "0")
 	parts := InputParts{Diagnostics: []string{"warn1"}, Selection: "code"}
 	client := &stubChatDoer{}
-	cfg := appconfig.Load(nil)
+	cfg := appconfig.Load(context.Background(), nil)
 	if _, err := handleDiagnosticsAction(context.Background(), parts, &cfg, client); err != nil {
 		t.Fatalf("handleDiagnosticsAction: %v", err)
 	}
@@ -84,7 +84,7 @@ func TestHandleSimplifyActionPassesSelection(t *testing.T) {
 	t.Setenv("HEXAI_TMUX_STATUS", "0")
 	parts := InputParts{Selection: "value := 1"}
 	client := &stubChatDoer{}
-	cfg := appconfig.Load(nil)
+	cfg := appconfig.Load(context.Background(), nil)
 	if _, err := handleSimplifyAction(context.Background(), parts, &cfg, client); err != nil {
 		t.Fatalf("handleSimplifyAction: %v", err)
 	}
@@ -107,7 +107,7 @@ func TestHandleCustomActionUsesProvidedCustom(t *testing.T) {
 	sel := appconfig.CustomAction{ID: "custom", Title: "Do", Instruction: "do it"}
 	parts := InputParts{Selection: "text"}
 	client := &stubChatDoer{}
-	cfg := appconfig.Load(nil)
+	cfg := appconfig.Load(context.Background(), nil)
 	if _, err := handleCustomAction(context.Background(), parts, &cfg, client, &sel); err != nil {
 		t.Fatalf("handleCustomAction: %v", err)
 	}