feat: AI suggestion (#34)

## Feat
* feat(ai): add AI suggestion engine, context gathering, and ghost text
overlay (`v0.3.0`)

## Security & Perf
* fix(ai): restrict background `--help` execution to a hardcoded command
allowlist to prevent RCE
* fix(root): defer context cancellation in goroutine to prevent resource
leaks
* perf(ai): implement LRU eviction and maximum size limit for
`ProviderCache`
* perf(ai): truncate command context output
(`CommandContextProvider.Gather`) to 1000 characters to save tokens

## Bug Fixes
* fix(ai): add mutex synchronization and thread-safe snapshotting to
`AIEngine.RegisterProvider` and `GatherDynamicContext`
* fix(ai): return a copy of fresh `Suggestion` in `AIEngine.Suggest` to
prevent cache mutation
* fix(ai): use length-prefixed encoding in `EnvSnapshot.Hash` to prevent
delimiter collisions
* fix(ai): skip variable assignment lines containing `=` when extracting
Makefile targets
* fix(runner): check `scanner.Err()` and return `nil` on scan errors in
justfile generator
* test(ci): rename `git commit` to `git checkout` in overlay test to
resolve CI `typos` false positive

commands/runner/justfile.go

@@ -3,6 +3,7 @@ package runner
 import (
 	"bufio"
 	"os"
+	"path/filepath"
 	"regexp"
 	"strings"
 
@@ -15,10 +16,11 @@ func init() {
 		Description: "command runner",
 		MaxArgs:     1,
 		Generator: func(tokens []string, prefix string, partial string) []spec.Suggestion {
-			file, err := os.Open("justfile")
+			cwd := spec.GetCWD()
+			file, err := os.Open(filepath.Join(cwd, "justfile"))
 			if err != nil {
 				// try uppercase
-				file, err = os.Open("Justfile")
+				file, err = os.Open(filepath.Join(cwd, "Justfile"))
 				if err != nil {
 					return nil
 				}
@@ -74,6 +76,9 @@ func init() {
 					}
 				}
 			}
+			if err := scanner.Err(); err != nil {
+				return nil
+			}
 			return suggestions
 		},
 	})

commands/runner/makefile.go

@@ -3,6 +3,7 @@ package runner
 import (
 	"bufio"
 	"os"
+	"path/filepath"
 	"regexp"
 
 	"github.com/versenilvis/iris/spec"
@@ -14,7 +15,8 @@ func init() {
 		Description: "build automation",
 		Generator: func(tokens []string, prefix string, partial string) []spec.Suggestion {
 			// Read the Makefile
-			file, err := os.Open("Makefile")
+			cwd := spec.GetCWD()
+			file, err := os.Open(filepath.Join(cwd, "Makefile"))
 			if err != nil {
 				// No Makefile, don't pretend we have one
 				return nil
@@ -48,6 +50,7 @@ func init() {
 					})
 				}
 			}
+			_ = scanner.Err()
 			return suggestions
 		},
 	})