feat(session-manager): add project path filtering for session listing

- Add SESSION_STORAGE constant for session metadata directory
- Add getMainSessions() function to retrieve main sessions with filtering:
  - Sorts sessions by updated time (newest first)
  - Filters out child sessions (with parentID)
  - Filters sessions by directory path
- Update session_list tool to use new getMainSessions():
  - Add project_path parameter (default: current working directory)
  - Maintains existing date range filtering and limit behavior

🤖 Generated with assistance of OhMyOpenCode

src/tools/session-manager/constants.ts

@@ -5,6 +5,7 @@ import { getClaudeConfigDir } from "../../shared"
 export const OPENCODE_STORAGE = getOpenCodeStorageDir()
 export const MESSAGE_STORAGE = join(OPENCODE_STORAGE, "message")
 export const PART_STORAGE = join(OPENCODE_STORAGE, "part")
+export const SESSION_STORAGE = join(OPENCODE_STORAGE, "session")
 export const TODO_DIR = join(getClaudeConfigDir(), "todos")
 export const TRANSCRIPT_DIR = join(getClaudeConfigDir(), "transcripts")
 export const SESSION_LIST_DESCRIPTION = `List all OpenCode sessions with optional filtering.