feat: migrate CLAUDE.md content to OpenSpec specs and initialize workflow

Move project description and tech stack research from CLAUDE.md into
openspec/specs/project/ and openspec/specs/stack/. Slim CLAUDE.md to a
pointer file. Populate config.yaml with project context. Add OpenSpec
CLI skills and commands.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

openspec/specs/chat-ui/spec.md

@@ -0,0 +1,70 @@
+## Purpose
+
+Define the chat interface — message display, input handling, auto-scroll, and routing.
+
+## Requirements
+
+### Requirement: Message display
+
+The chat page SHALL display messages in a vertically scrolling list, with each message showing the sender role (user or assistant), the message content, and a visual distinction between user and assistant messages (e.g., alignment, color, or avatar).
+
+#### Scenario: User message displayed
+
+- **WHEN** the user sends a message
+- **THEN** the message appears in the message list aligned or styled to indicate it is from the user
+
+#### Scenario: Assistant message displayed
+
+- **WHEN** the assistant responds
+- **THEN** the response appears in the message list with distinct styling from user messages (different alignment, color, or avatar)
+
+#### Scenario: Message ordering
+
+- **WHEN** multiple messages exist in the conversation
+- **THEN** messages are displayed in chronological order, oldest at top
+
+### Requirement: Message input
+
+The chat page SHALL provide a text input area at the bottom of the page where the user can type and submit messages.
+
+#### Scenario: Submit via button
+
+- **WHEN** the user types text and clicks the send button
+- **THEN** the message is added to the conversation and the input is cleared
+
+#### Scenario: Submit via Enter key
+
+- **WHEN** the user types text and presses Enter
+- **THEN** the message is submitted (same as clicking send)
+
+#### Scenario: Empty input blocked
+
+- **WHEN** the user attempts to send an empty or whitespace-only message
+- **THEN** nothing is sent and no message is added
+
+### Requirement: Hardcoded response
+
+In this phase, the assistant SHALL reply with a hardcoded message to every user input. This stubs the AI integration point for future phases.
+
+#### Scenario: Bot replies to any input
+
+- **WHEN** the user sends any message
+- **THEN** the assistant replies with a hardcoded response (e.g., "This is a placeholder response. AI integration coming soon!")
+
+### Requirement: Auto-scroll
+
+The message list SHALL automatically scroll to the newest message when a new message is added.
+
+#### Scenario: New message scrolls into view
+
+- **WHEN** a new message (user or assistant) is added to the conversation
+- **THEN** the message list scrolls to the bottom so the new message is visible
+
+### Requirement: Chat page is default route
+
+The chat page SHALL be the default route (`/`) of the application.
+
+#### Scenario: App opens to chat
+
+- **WHEN** the user navigates to the root URL
+- **THEN** the chat page is displayed