feat: add TypeScript declaration files for all core libraries

Add .d.ts type definitions for all four library modules:
- utils.d.ts: Platform detection, file ops, hook I/O, git helpers
- package-manager.d.ts: PM detection with PackageManagerName union type,
  DetectionSource union, and typed config interfaces
- session-manager.d.ts: Session CRUD with Session, SessionMetadata,
  SessionStats, and SessionListResult interfaces
- session-aliases.d.ts: Alias management with typed result interfaces
  for set, delete, rename, and cleanup operations

These provide IDE autocomplete and type-checking for TypeScript
consumers of the npm package without converting the source to TS.

scripts/lib/session-aliases.d.ts

@@ -0,0 +1,136 @@
+/**
+ * Session Aliases Library for Claude Code.
+ * Manages named aliases for session files, stored in ~/.claude/session-aliases.json.
+ */
+
+/** Internal alias storage entry */
+export interface AliasEntry {
+  sessionPath: string;
+  createdAt: string;
+  updatedAt?: string;
+  title: string | null;
+}
+
+/** Alias data structure stored on disk */
+export interface AliasStore {
+  version: string;
+  aliases: Record<string, AliasEntry>;
+  metadata: {
+    totalCount: number;
+    lastUpdated: string;
+  };
+}
+
+/** Resolved alias information returned by resolveAlias */
+export interface ResolvedAlias {
+  alias: string;
+  sessionPath: string;
+  createdAt: string;
+  title: string | null;
+}
+
+/** Alias entry returned by listAliases */
+export interface AliasListItem {
+  name: string;
+  sessionPath: string;
+  createdAt: string;
+  updatedAt?: string;
+  title: string | null;
+}
+
+/** Result from mutation operations (set, delete, rename, update, cleanup) */
+export interface AliasResult {
+  success: boolean;
+  error?: string;
+  [key: string]: unknown;
+}
+
+export interface SetAliasResult extends AliasResult {
+  isNew?: boolean;
+  alias?: string;
+  sessionPath?: string;
+  title?: string | null;
+}
+
+export interface DeleteAliasResult extends AliasResult {
+  alias?: string;
+  deletedSessionPath?: string;
+}
+
+export interface RenameAliasResult extends AliasResult {
+  oldAlias?: string;
+  newAlias?: string;
+  sessionPath?: string;
+}
+
+export interface CleanupResult {
+  totalChecked: number;
+  removed: number;
+  removedAliases: Array<{ name: string; sessionPath: string }>;
+  error?: string;
+}
+
+export interface ListAliasesOptions {
+  /** Filter aliases by name or title (partial match, case-insensitive) */
+  search?: string | null;
+  /** Maximum number of aliases to return */
+  limit?: number | null;
+}
+
+/** Get the path to the aliases JSON file */
+export function getAliasesPath(): string;
+
+/** Load all aliases from disk. Returns default structure if file doesn't exist. */
+export function loadAliases(): AliasStore;
+
+/**
+ * Save aliases to disk with atomic write (temp file + rename).
+ * Creates backup before writing; restores on failure.
+ */
+export function saveAliases(aliases: AliasStore): boolean;
+
+/**
+ * Resolve an alias name to its session data.
+ * @returns Alias data, or null if not found or invalid name
+ */
+export function resolveAlias(alias: string): ResolvedAlias | null;
+
+/**
+ * Create or update an alias for a session.
+ * Alias names must be alphanumeric with dashes/underscores.
+ * Reserved names (list, help, remove, delete, create, set) are rejected.
+ */
+export function setAlias(alias: string, sessionPath: string, title?: string | null): SetAliasResult;
+
+/**
+ * List all aliases, optionally filtered and limited.
+ * Results are sorted by updated time (newest first).
+ */
+export function listAliases(options?: ListAliasesOptions): AliasListItem[];
+
+/** Delete an alias by name */
+export function deleteAlias(alias: string): DeleteAliasResult;
+
+/**
+ * Rename an alias. Fails if old alias doesn't exist or new alias already exists.
+ * New alias name must be alphanumeric with dashes/underscores.
+ */
+export function renameAlias(oldAlias: string, newAlias: string): RenameAliasResult;
+
+/**
+ * Resolve an alias or pass through a session path.
+ * First tries to resolve as alias; if not found, returns the input as-is.
+ */
+export function resolveSessionAlias(aliasOrId: string): string;
+
+/** Update the title of an existing alias */
+export function updateAliasTitle(alias: string, title: string): AliasResult;
+
+/** Get all aliases that point to a specific session path */
+export function getAliasesForSession(sessionPath: string): Array<{ name: string; createdAt: string; title: string | null }>;
+
+/**
+ * Remove aliases whose sessions no longer exist.
+ * @param sessionExists - Function that returns true if a session path is valid
+ */
+export function cleanupAliases(sessionExists: (sessionPath: string) => boolean): CleanupResult;