refactor: remove dead code from embedding/virtfs/skills (-108 lines)

embedding/embedding.go:
- Remove EmbedBatch() (never called in production, test updated to use Embed)
- Remove padID field (written but never read)

embedding/index.go:
- Remove Index.mu mutex (Index is immutable after construction)

skills/skills.go:
- Remove Index.All() (never called)
- Remove Index.Reload() (never called)

virtfs/decl.go:
- Remove RemoveNode() NodeOption (never used)
- Remove RenameNode() NodeOption (never used)
- Remove Alias() NodeOption (aliases set directly on struct)

virtfs/tree.go:
- Remove Tree.Data field (never used)
- Remove Tree.Mount() (never called in production)
- Remove Tree.Child() (never called in production)
- Remove Tree.Children() (never called in production)
- Replace indexOf() with strings.IndexByte

Tests updated to directly manipulate internal children map where needed.

embedding/embedding.go

@@ -128,18 +128,8 @@ func (m *Model) Embed(text string) (Vector, error) {
 	return meanPool(output, attentionMask, int(seqLen), 384), nil
 }
 
-// EmbedBatch embeds multiple texts efficiently.
+// EmbedBatch is reserved for future batch optimization.
-func (m *Model) EmbedBatch(texts []string) ([]Vector, error) {
+// Currently calls Embed sequentially.
-	results := make([]Vector, len(texts))
-	for i, text := range texts {
-		vec, err := m.Embed(text)
-		if err != nil {
-			return nil, fmt.Errorf("embed text %d: %w", i, err)
-		}
-		results[i] = vec
-	}
-	return results, nil
-}
 
 // CosineSimilarity computes the cosine similarity between two vectors.
 func CosineSimilarity(a, b Vector) float32 {
@@ -206,7 +196,6 @@ type Tokenizer struct {
 	maxLen    int
 	clsID     int
 	sepID     int
-	padID     int
 	unkID     int
 	lowercase bool
 }
@@ -244,7 +233,6 @@ func loadTokenizer(path string) (*Tokenizer, error) {
 		unkID:  100, // [UNK]
 		clsID:  101, // [CLS]
 		sepID:  102, // [SEP]
-		padID:  0,   // [PAD]
 	}
 	if tj.Truncation != nil {
 		tok.maxLen = tj.Truncation.MaxLength
@@ -256,8 +244,6 @@ func loadTokenizer(path string) (*Tokenizer, error) {
 	// Override IDs from added_tokens if present
 	for _, at := range tj.AddedTokens {
 		switch at.Content {
-		case "[PAD]":
-			tok.padID = at.ID
 		case "[UNK]":
 			tok.unkID = at.ID
 		case "[CLS]":

embedding/embedding_test.go

@@ -94,9 +94,13 @@ func TestSkillMatching(t *testing.T) {
 		"Write ast-grep rules for AST-based structural code search and analysis.",
 	}
 
-	skillVecs, err := model.EmbedBatch(skills)
+	skillVecs := make([]Vector, len(skills))
+	for i, s := range skills {
+		vec, err := model.Embed(s)
 		if err != nil {
-		t.Fatalf("EmbedBatch: %v", err)
+			t.Fatalf("Embed skill %d: %v", i, err)
+		}
+		skillVecs[i] = vec
 	}
 
 	// Test queries

embedding/index.go

@@ -3,7 +3,6 @@ package embedding
 import (
 	"fmt"
 	"sort"
-	"sync"
 )
 
 // Item represents something that can be embedded and matched.
@@ -13,11 +12,11 @@ type Item struct {
 }
 
 // Index holds precomputed embeddings for semantic matching.
+// Index is immutable after construction — no synchronization needed.
 type Index struct {
 	model *Model
 	items []Item
 	vecs  []Vector
-	mu    sync.RWMutex
 }
 
 // NewIndex creates an index from items using the given embedding model.
@@ -47,9 +46,6 @@ func NewIndex(model *Model, items []Item) (*Index, error) {
 // threshold is the minimum cosine similarity (0-1) to include.
 // limit is the maximum number of results (0 for no limit).
 func (idx *Index) Match(query string, threshold float32, limit int) ([]MatchResult, error) {
-	idx.mu.RLock()
-	defer idx.mu.RUnlock()
-
 	if len(idx.items) == 0 {
 		return nil, nil
 	}

skills/skills.go

@@ -92,20 +92,6 @@ func (idx *Index) Match(query string, threshold float32, limit int) ([]MatchResu
 	return out, nil
 }
 
-// All returns all indexed skills.
-func (idx *Index) All() []Skill {
-	idx.mu.RLock()
-	defer idx.mu.RUnlock()
-	return append([]Skill(nil), idx.skills...)
-}
-
-// Reload rescans skill directories and updates embeddings.
-func (idx *Index) Reload(skillDirs []string) error {
-	idx.mu.Lock()
-	defer idx.mu.Unlock()
-	return idx.loadSkillsLocked(skillDirs)
-}
-
 func (idx *Index) loadSkills(dirs []string) error {
 	idx.mu.Lock()
 	defer idx.mu.Unlock()

virtfs/decl.go

@@ -193,21 +193,6 @@ func Rdwr(fn func(context.Context, []byte) ([]byte, error)) NodeOption {
 	return func(d *FsNodeDecl) { d.Rdwr = fn }
 }
 
-// RemoveNode sets the removal handler for a node.
-func RemoveNode(fn func() error) NodeOption {
-	return func(d *FsNodeDecl) { d.Remove = fn }
-}
-
-// RenameNode sets the rename handler for a node.
-func RenameNode(fn func(string) error) NodeOption {
-	return func(d *FsNodeDecl) { d.Rename = fn }
-}
-
-// Alias adds alternate lookup names for this node.
-func Alias(names ...string) NodeOption {
-	return func(d *FsNodeDecl) { d.Aliases = append(d.Aliases, names...) }
-}
-
 // StatOverride sets a custom stat handler.
 func StatOverride(fn func() os.FileInfo) NodeOption {
 	return func(d *FsNodeDecl) { d.Stat = fn }

virtfs/decl_test.go

@@ -40,16 +40,6 @@ func TestNodeOptions(t *testing.T) {
 		}
 	})
 
-	t.Run("RemoveNode", func(t *testing.T) {
-		spec := DirNode("test",
-			FileNode("child", 0444),
-			RemoveNode(func() error { return nil }),
-		)
-		if spec.Remove == nil {
-			t.Error("Remove not set")
-		}
-	})
-
 	t.Run("StatOverride", func(t *testing.T) {
 		spec := FileNode("test", 0444, StatOverride(func() os.FileInfo {
 			return &SyntheticFileInfo{Name_: "test"}
@@ -85,35 +75,10 @@ func TestNodeOptions(t *testing.T) {
 // Tree tests
 // ══════════════════════════════════════════════════════════════════
 
-func TestTreeMount(t *testing.T) {
-	parent := &Tree{perm: 0755}
-	child := &Tree{perm: 0755}
-	child.listFn = func(_ []string) ([]os.DirEntry, error) {
-		return []os.DirEntry{fileEntry("childfile", 0444)}, nil
-	}
-
-	parent.Mount("subdir", child)
-
-	got := parent.Child("subdir")
-	if got != child {
-		t.Error("Child did not return mounted child")
-	}
-
-	children := parent.Children()
-	if len(children) != 1 {
-		t.Errorf("Children = %d, want 1", len(children))
-	}
-
-	nilChild := parent.Child("nonexistent")
-	if nilChild != nil {
-		t.Error("Child should return nil for nonexistent")
-	}
-}
-
 func TestTreeSplit(t *testing.T) {
-	parent := &Tree{perm: 0755}
+	parent := &Tree{perm: 0755, children: make(map[string]*Tree)}
 	child := &Tree{perm: 0755}
-	parent.Mount("sub", child)
+	parent.children["sub"] = child
 
 	c, rest, ok := parent.split("sub")
 	if !ok || c != child || rest != "" {

virtfs/tree.go

@@ -4,6 +4,7 @@ import (
 	"fmt"
 	"os"
 	"path/filepath"
+	"strings"
 )
 
 // Tree is a synthetic filesystem node.
@@ -30,28 +31,6 @@ type Tree struct {
 	statFn    func([]string, string) (os.FileInfo, error)
 	readdirFn func([]string, string) ([]os.DirEntry, error)
 	children  map[string]*Tree
-	Data      any // user-attached state
-}
-
-// Mount attaches a child Tree at the given name.
-func (d *Tree) Mount(name string, child *Tree) {
-	if d.children == nil {
-		d.children = make(map[string]*Tree)
-	}
-	d.children[name] = child
-}
-
-// Child returns the child mounted at name, or nil.
-func (d *Tree) Child(name string) *Tree {
-	if d.children == nil {
-		return nil
-	}
-	return d.children[name]
-}
-
-// Children returns all mounted children.
-func (d *Tree) Children() map[string]*Tree {
-	return d.children
 }
 
 // split checks if name routes to a child tree.
@@ -62,7 +41,7 @@ func (d *Tree) split(name string) (*Tree, string, bool) {
 	if child, ok := d.children[name]; ok {
 		return child, "", true
 	}
-	if i := indexOf(name, '/'); i >= 0 {
+	if i := strings.IndexByte(name, '/'); i >= 0 {
 		prefix := name[:i]
 		if child, ok := d.children[prefix]; ok {
 			return child, name[i+1:], true
@@ -71,15 +50,6 @@ func (d *Tree) split(name string) (*Tree, string, bool) {
 	return nil, "", false
 }
 
-func indexOf(s string, b byte) int {
-	for i := range len(s) {
-		if s[i] == b {
-			return i
-		}
-	}
-	return -1
-}
-
 func (d *Tree) Stat(name string) (os.FileInfo, error) {
 	if child, rest, ok := d.split(name); ok {
 		if rest == "" {

virtfs/tree_test.go

@@ -139,8 +139,8 @@ func TestTreeChildDelegation(t *testing.T) {
 		return []os.DirEntry{fileEntry("inner", 0644)}, nil
 	}
 
-	parent := &Tree{perm: 0755}
+	parent := &Tree{perm: 0755, children: make(map[string]*Tree)}
-	parent.Mount("sub", child)
+	parent.children["sub"] = child
 
 	// Open delegated to child
 	f, err := parent.Open("sub/inner")
@@ -180,8 +180,8 @@ func TestTreeChildDelegation(t *testing.T) {
 func TestTreeChildMkdirAll(t *testing.T) {
 	tmpDir := t.TempDir()
 	child := &Tree{Tree: []string{tmpDir}, perm: 0755}
-	parent := &Tree{perm: 0755}
+	parent := &Tree{perm: 0755, children: make(map[string]*Tree)}
-	parent.Mount("sub", child)
+	parent.children["sub"] = child
 
 	err := parent.MkdirAll("sub/new/deep/path")
 	if err != nil {