feat(skills): add agent-browser option for browser automation (#1090)

Add configurable browser automation allowing users to choose between
Playwright MCP (default) and Vercel's agent-browser CLI.

Changes:
- Add browser_automation_engine.provider config option
- Dynamic skill loading based on provider selection
- Comprehensive agent-browser CLI reference (inline in skills.ts)
- Propagate browserProvider to delegate_task and buildAgent
- Update documentation with provider comparison

Co-authored-by: Suyeol Jeon <devxoul@gmail.com>
Co-authored-by: YeonGyu Kim <code.yeongyu@gmail.com>

src/features/opencode-skill-loader/skill-content.test.ts

@@ -265,3 +265,66 @@ describe("resolveMultipleSkillsAsync", () => {
 		expect(result.notFound).toEqual([])
 	})
 })
+
+describe("resolveSkillContent with browserProvider", () => {
+	it("should resolve agent-browser skill when browserProvider is 'agent-browser'", () => {
+		// #given: browserProvider set to agent-browser
+		const options = { browserProvider: "agent-browser" as const }
+
+		// #when: resolving content for 'agent-browser'
+		const result = resolveSkillContent("agent-browser", options)
+
+		// #then: returns agent-browser template
+		expect(result).not.toBeNull()
+		expect(result).toContain("agent-browser")
+	})
+
+	it("should return null for agent-browser when browserProvider is default", () => {
+		// #given: no browserProvider (defaults to playwright)
+
+		// #when: resolving content for 'agent-browser'
+		const result = resolveSkillContent("agent-browser")
+
+		// #then: returns null because agent-browser is not in default builtin skills
+		expect(result).toBeNull()
+	})
+
+	it("should return null for playwright when browserProvider is agent-browser", () => {
+		// #given: browserProvider set to agent-browser
+		const options = { browserProvider: "agent-browser" as const }
+
+		// #when: resolving content for 'playwright'
+		const result = resolveSkillContent("playwright", options)
+
+		// #then: returns null because playwright is replaced by agent-browser
+		expect(result).toBeNull()
+	})
+})
+
+describe("resolveMultipleSkills with browserProvider", () => {
+	it("should resolve agent-browser when browserProvider is set", () => {
+		// #given: agent-browser and git-master requested with browserProvider
+		const skillNames = ["agent-browser", "git-master"]
+		const options = { browserProvider: "agent-browser" as const }
+
+		// #when: resolving multiple skills
+		const result = resolveMultipleSkills(skillNames, options)
+
+		// #then: both resolved
+		expect(result.resolved.has("agent-browser")).toBe(true)
+		expect(result.resolved.has("git-master")).toBe(true)
+		expect(result.notFound).toHaveLength(0)
+	})
+
+	it("should not resolve agent-browser without browserProvider option", () => {
+		// #given: agent-browser requested without browserProvider
+		const skillNames = ["agent-browser"]
+
+		// #when: resolving multiple skills
+		const result = resolveMultipleSkills(skillNames)
+
+		// #then: agent-browser not found
+		expect(result.resolved.has("agent-browser")).toBe(false)
+		expect(result.notFound).toContain("agent-browser")
+	})
+})