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, 2 insertions, 2 deletions

diff --git a/internal/hexaiaction/run.go b/internal/hexaiaction/run.go
index 92aa72d..f0ce7ee 100644
--- a/internal/hexaiaction/run.go
+++ b/internal/hexaiaction/run.go
@@ -114,7 +114,7 @@ func (tmuxActionStatusSink) SetLLMStart(provider, model string) error {
 }
 
 func loadActionConfig(ctx context.Context, logger *log.Logger) appconfig.App {
-	return appconfig.LoadWithOptions(logger, appconfig.LoadOptions{ConfigPath: configPathFromContext(ctx)})
+	return appconfig.LoadWithOptions(ctx, logger, appconfig.LoadOptions{ConfigPath: configPathFromContext(ctx)})
 }
 
 type actionPlan struct {
@@ -381,7 +381,7 @@ func handleCustomAction(ctx context.Context, parts InputParts, cfg actionConfig,
 }
 
 func handleCustomPromptAction(ctx context.Context, parts InputParts, cfg actionConfig, client chatDoer, stderr io.Writer) (string, error) {
-	prompt, err := editor.OpenTempAndEdit(nil)
+	prompt, err := editor.OpenTempAndEdit(ctx, nil)
 	if err != nil || strings.TrimSpace(prompt) == "" {
 		_, _ = fmt.Fprintln(stderr, logging.AnsiBase+"hexai-tmux-action: custom prompt canceled or empty; echoing input"+logging.AnsiReset)
 		return parts.Selection, nil