speckit-implement

## User Input ```text $ARGUMENTS ``` You **MUST** consider the user input before proceeding (if not empty). ## Pre-Execution Checks **Check for extension hooks (before implementation)**: - Check if `.specify/extensions.yml` exists in the project root. - If it exists, read it and look for entries under the `hooks.before_implement` key - If the YAML cannot be parsed or is invalid, skip hook checking silently and continue normally - Filter out hooks where `enabled` is explicitly `false`. Treat hooks without an `enabled` field as enabled by default. - For each remaining hook, do **not** attempt to interpret or evaluate hook `condition` expressions: - If the hook has no `condition` field, or it is null/empty, treat the hook as executable - If the hook defines a non-empty `condition`, skip the hook and leave condition evaluation to the HookExecutor implementation - For each executable hook, output the following based on its `optional` flag: - **Optional hook** (`optional: true`): ``` ## Extension Hooks **Optional Pre-Hook**: {extension} Command: `/{command}` Description: {description} Prompt: {prompt} To execute: `/{command}` ``` - **Mandatory hook** (`optional: false`): ``` ## Extension Hooks **Automatic Pre-Hook**: {extension} Executing: `/{command}` EXECUTE_COMMAND: {command} Wait for the result of the hook command before proceeding to the Outline. ``` - If no hooks are registered or `.specify/extens...