feat(speckit): integrate github/spec-kit for spec-driven development (#38)

Installs spec-kit slash commands (/speckit-specify, /speckit-plan,
/speckit-tasks, /speckit-implement, /speckit-analyze, /speckit-clarify,
/speckit-checklist, /speckit-constitution, /speckit-taskstoissues) into
Claude Code via .claude/skills/speckit-*/.

Note: specify-cli v1.0.0 init fails on Windows because spec-kit v0.5+
releases no longer attach binary zip assets to GitHub releases (confirmed
by inspecting all 30 releases via API; only v0.4.4 and earlier have
assets). Templates were sourced directly from the github/spec-kit@v0.7.3
repo tree and SKILL.md files were built per the claude integration spec
in src/specify_cli/integrations/claude/__init__.py (user-invocable:true,
disable-model-invocation:false, argument-hint injection).

Enables the "specs in git" workflow for cross-device work state:
- New feature → /speckit-specify → specs/NNN/spec.md
- Design → /speckit-plan → specs/NNN/plan.md
- Work → /speckit-tasks → specs/NNN/tasks.md (handoff artifact)
- Implement → /speckit-implement → code

Preserves existing CLAUDE.md (@AGENTS.md bridges intact) and existing
memory policies in AGENTS.md. memory/constitution.md is annotated at
the top to reference AGENTS.md for project-specific constraints.

No change to server.mjs, models.json, package.json, or any other code.

Co-authored-by: Tao Deng <dtzp555@gmail.com>
Co-authored-by: Claude Sonnet 4.6 <noreply@anthropic.com>

.claude/skills/speckit-taskstoissues/SKILL.md

@@ -0,0 +1,101 @@
+---
+name: speckit-taskstoissues
+description: Convert existing tasks into actionable, dependency-ordered GitHub issues for the feature based on available design artifacts.
+argument-hint: "Optional filter or label for GitHub issues"
+user-invocable: true
+disable-model-invocation: false
+---
+
+## User Input
+
+```text
+$ARGUMENTS
+```
+
+You **MUST** consider the user input before proceeding (if not empty).
+
+## Pre-Execution Checks
+
+**Check for extension hooks (before tasks-to-issues conversion)**:
+- Check if `.specify/extensions.yml` exists in the project root.
+- If it exists, read it and look for entries under the `hooks.before_taskstoissues` 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
+- When constructing slash commands from hook command names, replace dots (`.`) with hyphens (`-`). For example, `speckit.git.commit` -> `/speckit-git-commit`.
+- 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/extensions.yml` does not exist, skip silently
+
+## Outline
+
+1. Run `{SCRIPT}` from repo root and parse FEATURE_DIR and AVAILABLE_DOCS list. All paths must be absolute. For single quotes in args like "I'm Groot", use escape syntax: e.g 'I'\''m Groot' (or double-quote if possible: "I'm Groot").
+1. From the executed script, extract the path to **tasks**.
+1. Get the Git remote by running:
+
+```bash
+git config --get remote.origin.url
+```
+
+> [!CAUTION]
+> ONLY PROCEED TO NEXT STEPS IF THE REMOTE IS A GITHUB URL
+
+1. For each task in the list, use the GitHub MCP server to create a new issue in the repository that is representative of the Git remote.
+
+> [!CAUTION]
+> UNDER NO CIRCUMSTANCES EVER CREATE ISSUES IN REPOSITORIES THAT DO NOT MATCH THE REMOTE URL
+
+## Post-Execution Checks
+
+**Check for extension hooks (after tasks-to-issues conversion)**:
+Check if `.specify/extensions.yml` exists in the project root.
+- If it exists, read it and look for entries under the `hooks.after_taskstoissues` 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
+- When constructing slash commands from hook command names, replace dots (`.`) with hyphens (`-`). For example, `speckit.git.commit` -> `/speckit-git-commit`.
+- For each executable hook, output the following based on its `optional` flag:
+  - **Optional hook** (`optional: true`):
+    ```
+    ## Extension Hooks
+
+    **Optional Hook**: {extension}
+    Command: `/{command}`
+    Description: {description}
+
+    Prompt: {prompt}
+    To execute: `/{command}`
+    ```
+  - **Mandatory hook** (`optional: false`):
+    ```
+    ## Extension Hooks
+
+    **Automatic Hook**: {extension}
+    Executing: `/{command}`
+    EXECUTE_COMMAND: {command}
+    ```
+- If no hooks are registered or `.specify/extensions.yml` does not exist, skip silently