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, 12 insertions, 4 deletions

diff --git a/cmd/hexai-mcp-server/main.go b/cmd/hexai-mcp-server/main.go
index ac88178..03150bb 100644
--- a/cmd/hexai-mcp-server/main.go
+++ b/cmd/hexai-mcp-server/main.go
@@ -2,11 +2,14 @@
 package main
 
 import (
+	"context"
 	"flag"
 	"fmt"
 	"io"
 	"os"
+	"os/signal"
 	"path/filepath"
+	"syscall"
 
 	"codeberg.org/snonux/hexai/internal"
 	"codeberg.org/snonux/hexai/internal/appconfig"
@@ -100,7 +103,11 @@ func runMain(args []string, stdin io.Reader, stdout, stderr io.Writer) int {
 		syncAll:          *syncAll,
 		showVersion:      *showVersion,
 	}
-	if err := run(opts, stdin, stdout, stderr); err != nil {
+	// Cancel the run on interrupt/terminate so the serve loop exits cleanly.
+	ctx, stop := signal.NotifyContext(context.Background(), os.Interrupt, syscall.SIGTERM)
+	defer stop()
+
+	if err := run(ctx, opts, stdin, stdout, stderr); err != nil {
 		fmt.Fprintf(stderr, "error: %v\n", err)
 		return 1
 	}
@@ -109,7 +116,8 @@ func runMain(args []string, stdin io.Reader, stdout, stderr io.Writer) int {
 
 // run executes the MCP server logic with the given options and I/O streams.
 // CLI flag values are passed via MCPOverrides instead of environment variables.
-func run(opts mcpOptions, stdin io.Reader, stdout, stderr io.Writer) error {
+// ctx is threaded into the server/backfill so they stop on shutdown signals.
+func run(ctx context.Context, opts mcpOptions, stdin io.Reader, stdout, stderr io.Writer) error {
 	if opts.showVersion {
 		fmt.Fprintln(stdout, internal.Version)
 		return nil
@@ -119,10 +127,10 @@ func run(opts mcpOptions, stdin io.Reader, stdout, stderr io.Writer) error {
 
 	// Handle backfill operation
 	if opts.syncAll {
-		return runBackfill(opts.logPath, opts.configPath, overrides)
+		return runBackfill(ctx, opts.logPath, opts.configPath, overrides)
 	}
 
-	return runMCP(opts.logPath, opts.configPath, overrides, stdin, stdout, stderr)
+	return runMCP(ctx, opts.logPath, opts.configPath, overrides, stdin, stdout, stderr)
 }
 
 // defaultLogPath returns the default MCP log file path in the state directory.