feat(tools): add session management tools for OpenCode sessions (#227)

* feat(tools): add session management tools for OpenCode sessions

- Add session_list tool for listing sessions with filtering
- Add session_read tool for reading session messages and history
- Add session_search tool for full-text search across sessions
- Add session_info tool for session metadata inspection
- Add comprehensive tests for storage, utils, and tools
- Update documentation in AGENTS.md

Closes #132

* fix(session-manager): add Windows compatibility for storage paths

- Create shared/data-path.ts utility for cross-platform data directory resolution
- On Windows: uses %LOCALAPPDATA% (e.g., C:\Users\Username\AppData\Local)
- On Unix: uses $XDG_DATA_HOME or ~/.local/share (XDG Base Directory spec)
- Update session-manager/constants.ts to use getOpenCodeStorageDir()
- Update hook-message-injector/constants.ts to use same utility
- Remove dependency on xdg-basedir package in session-manager
- Follows existing pattern from auto-update-checker for consistency

---------

Co-authored-by: sisyphus-dev-ai <sisyphus-dev-ai@users.noreply.github.com>

src/tools/session-manager/tools.test.ts

@@ -0,0 +1,95 @@
+import { describe, test, expect } from "bun:test"
+import { session_list, session_read, session_search, session_info } from "./tools"
+
+describe("session-manager tools", () => {
+  test("session_list executes without error", async () => {
+    const result = await session_list.execute({})
+    
+    expect(typeof result).toBe("string")
+  })
+
+  test("session_list respects limit parameter", async () => {
+    const result = await session_list.execute({ limit: 5 })
+    
+    expect(typeof result).toBe("string")
+  })
+
+  test("session_list filters by date range", async () => {
+    const result = await session_list.execute({
+      from_date: "2025-12-01T00:00:00Z",
+      to_date: "2025-12-31T23:59:59Z",
+    })
+    
+    expect(typeof result).toBe("string")
+  })
+
+  test("session_read handles non-existent session", async () => {
+    const result = await session_read.execute({ session_id: "ses_nonexistent" })
+    
+    expect(result).toContain("not found")
+  })
+
+  test("session_read executes with valid parameters", async () => {
+    const result = await session_read.execute({
+      session_id: "ses_test123",
+      include_todos: true,
+      include_transcript: true,
+    })
+    
+    expect(typeof result).toBe("string")
+  })
+
+  test("session_read respects limit parameter", async () => {
+    const result = await session_read.execute({
+      session_id: "ses_test123",
+      limit: 10,
+    })
+    
+    expect(typeof result).toBe("string")
+  })
+
+  test("session_search executes without error", async () => {
+    const result = await session_search.execute({ query: "test" })
+    
+    expect(typeof result).toBe("string")
+  })
+
+  test("session_search filters by session_id", async () => {
+    const result = await session_search.execute({
+      query: "test",
+      session_id: "ses_test123",
+    })
+    
+    expect(typeof result).toBe("string")
+  })
+
+  test("session_search respects case_sensitive parameter", async () => {
+    const result = await session_search.execute({
+      query: "TEST",
+      case_sensitive: true,
+    })
+    
+    expect(typeof result).toBe("string")
+  })
+
+  test("session_search respects limit parameter", async () => {
+    const result = await session_search.execute({
+      query: "test",
+      limit: 5,
+    })
+    
+    expect(typeof result).toBe("string")
+  })
+
+  test("session_info handles non-existent session", async () => {
+    const result = await session_info.execute({ session_id: "ses_nonexistent" })
+    
+    expect(result).toContain("not found")
+  })
+
+  test("session_info executes with valid session", async () => {
+    const result = await session_info.execute({ session_id: "ses_test123" })
+    
+    expect(typeof result).toBe("string")
+  })
+})