fix(skill-loader): discover skills from parent config dir when using profiles

OPENCODE_CONFIG_DIR pointing to profiles/ subdirectory caused skills at
~/.config/opencode/skills/ to be invisible. Added getOpenCodeSkillDirs()
with the same parent-dir fallback that getOpenCodeCommandDirs() uses.

src/shared/opencode-command-dirs.test.ts

@@ -0,0 +1,66 @@
+import { describe, expect, it, mock, beforeEach, afterEach } from "bun:test"
+import { join } from "node:path"
+
+describe("opencode-command-dirs", () => {
+  let originalEnv: string | undefined
+
+  beforeEach(() => {
+    originalEnv = process.env.OPENCODE_CONFIG_DIR
+  })
+
+  afterEach(() => {
+    if (originalEnv !== undefined) {
+      process.env.OPENCODE_CONFIG_DIR = originalEnv
+    } else {
+      delete process.env.OPENCODE_CONFIG_DIR
+    }
+  })
+
+  describe("getOpenCodeSkillDirs", () => {
+    describe("#given config dir inside profiles/", () => {
+      describe("#when getOpenCodeSkillDirs is called", () => {
+        it("#then returns both profile and parent skill dirs", async () => {
+          process.env.OPENCODE_CONFIG_DIR = "/home/user/.config/opencode/profiles/opus"
+
+          const { getOpenCodeSkillDirs } = await import("./opencode-command-dirs")
+          const dirs = getOpenCodeSkillDirs({ binary: "opencode" })
+
+          expect(dirs).toContain("/home/user/.config/opencode/profiles/opus/skills")
+          expect(dirs).toContain("/home/user/.config/opencode/skills")
+          expect(dirs).toHaveLength(2)
+        })
+      })
+    })
+
+    describe("#given config dir NOT inside profiles/", () => {
+      describe("#when getOpenCodeSkillDirs is called", () => {
+        it("#then returns only the config dir skills", async () => {
+          process.env.OPENCODE_CONFIG_DIR = "/home/user/.config/opencode"
+
+          const { getOpenCodeSkillDirs } = await import("./opencode-command-dirs")
+          const dirs = getOpenCodeSkillDirs({ binary: "opencode" })
+
+          expect(dirs).toContain("/home/user/.config/opencode/skills")
+          expect(dirs).toHaveLength(1)
+        })
+      })
+    })
+  })
+
+  describe("getOpenCodeCommandDirs", () => {
+    describe("#given config dir inside profiles/", () => {
+      describe("#when getOpenCodeCommandDirs is called", () => {
+        it("#then returns both profile and parent command dirs", async () => {
+          process.env.OPENCODE_CONFIG_DIR = "/home/user/.config/opencode/profiles/opus"
+
+          const { getOpenCodeCommandDirs } = await import("./opencode-command-dirs")
+          const dirs = getOpenCodeCommandDirs({ binary: "opencode" })
+
+          expect(dirs).toContain("/home/user/.config/opencode/profiles/opus/command")
+          expect(dirs).toContain("/home/user/.config/opencode/command")
+          expect(dirs).toHaveLength(2)
+        })
+      })
+    })
+  })
+})