v0.1.13 — canonical PostToolUseFailure event, mapped for Goose

Added

• HookEventPostToolUseFailure: canonical constant for the failed-tool-call event. Agents that define it (Goose, Cursor) fire PostToolUse only on success, so without a mapping for the failure event a failed turn is invisible to a consumer until the next successful tool call or Stop. Cursor spells it camelCase (CursorEventPostToolUseFailure); the canonical constant uses Goose's PascalCase.
• Goose PostToolUseFailure → PhaseAfterTool: GooseAgent.EventPhases() now covers seven events. Goose's four remaining events (BeforeReadFile, AfterFileEdit, BeforeShellExecution, AfterShellExecution) stay deliberately unmapped — each is a strict subset of PreToolUse/PostToolUse, since reading a file and running a shell command are both tool calls, so mapping them would fire a consumer twice per tool call for no additional signal. That reasoning is now recorded on the method.