refactor: migrate from Bun.Glob to npm glob package

Replace Bun.Glob usage with a new Glob utility wrapper around the npm 'glob' package.
This moves us off Bun-specific APIs toward standard Node.js compatible solutions.

Changes:
- Add new src/util/glob.ts utility module with scan(), scanSync(), and match()
- Default include option is 'file' (only returns files, not directories)
- Add symlink option (default: false) to control symlink following
- Migrate all 12 files using Bun.Glob to use the new Glob utility
- Add comprehensive tests for the glob utility

Breaking changes:
- Removed support for include: 'dir' option (use include: 'all' and filter manually)
- symlink now defaults to false (was true in most Bun.Glob usages)

Files migrated:
- src/util/log.ts
- src/util/filesystem.ts
- src/tool/truncation.ts
- src/session/instruction.ts
- src/storage/json-migration.ts
- src/storage/storage.ts
- src/project/project.ts
- src/cli/cmd/tui/context/theme.tsx
- src/config/config.ts
- src/tool/registry.ts
- src/skill/skill.ts
- src/file/ignore.ts

packages/opencode/src/skill/skill.ts

@@ -12,6 +12,7 @@ import { Flag } from "@/flag/flag"
 import { Bus } from "@/bus"
 import { Session } from "@/session"
 import { Discovery } from "./discovery"
+import { Glob } from "../util/glob"
 
 export namespace Skill {
   const log = Log.create({ service: "skill" })
@@ -44,10 +45,9 @@ export namespace Skill {
   // External skill directories to search for (project-level and global)
   // These follow the directory layout used by Claude Code and other agents.
   const EXTERNAL_DIRS = [".claude", ".agents"]
-  const EXTERNAL_SKILL_GLOB = new Bun.Glob("skills/**/SKILL.md")
-
-  const OPENCODE_SKILL_GLOB = new Bun.Glob("{skill,skills}/**/SKILL.md")
-  const SKILL_GLOB = new Bun.Glob("**/SKILL.md")
+  const EXTERNAL_SKILL_PATTERN = "skills/**/SKILL.md"
+  const OPENCODE_SKILL_PATTERN = "{skill,skills}/**/SKILL.md"
+  const SKILL_PATTERN = "**/SKILL.md"
 
   export const state = Instance.state(async () => {
     const skills: Record<string, Info> = {}
@@ -88,15 +88,12 @@ export namespace Skill {
     }
 
     const scanExternal = async (root: string, scope: "global" | "project") => {
-      return Array.fromAsync(
-        EXTERNAL_SKILL_GLOB.scan({
-          cwd: root,
-          absolute: true,
-          onlyFiles: true,
-          followSymlinks: true,
-          dot: true,
-        }),
-      )
+      return Glob.scan(EXTERNAL_SKILL_PATTERN, {
+        cwd: root,
+        absolute: true,
+        include: "file",
+        dot: true,
+      })
         .then((matches) => Promise.all(matches.map(addSkill)))
         .catch((error) => {
           log.error(`failed to scan ${scope} skills`, { dir: root, error })
@@ -123,12 +120,12 @@ export namespace Skill {
 
     // Scan .opencode/skill/ directories
     for (const dir of await Config.directories()) {
-      for await (const match of OPENCODE_SKILL_GLOB.scan({
+      const matches = await Glob.scan(OPENCODE_SKILL_PATTERN, {
         cwd: dir,
         absolute: true,
-        onlyFiles: true,
-        followSymlinks: true,
-      })) {
+        include: "file",
+      })
+      for (const match of matches) {
         await addSkill(match)
       }
     }
@@ -142,12 +139,12 @@ export namespace Skill {
         log.warn("skill path not found", { path: resolved })
         continue
       }
-      for await (const match of SKILL_GLOB.scan({
+      const matches = await Glob.scan(SKILL_PATTERN, {
         cwd: resolved,
         absolute: true,
-        onlyFiles: true,
-        followSymlinks: true,
-      })) {
+        include: "file",
+      })
+      for (const match of matches) {
         await addSkill(match)
       }
     }
@@ -157,12 +154,12 @@ export namespace Skill {
       const list = await Discovery.pull(url)
       for (const dir of list) {
         dirs.add(dir)
-        for await (const match of SKILL_GLOB.scan({
+        const matches = await Glob.scan(SKILL_PATTERN, {
           cwd: dir,
           absolute: true,
-          onlyFiles: true,
-          followSymlinks: true,
-        })) {
+          include: "file",
+        })
+        for (const match of matches) {
           await addSkill(match)
         }
       }