feat: Implement node deletion with shared modal and fix SurrealDB RecordId handling

Implements complete node deletion functionality for both galaxy view and debug panel:

**Core Changes:**
- Created shared DeleteNodeModal component used by both ThoughtGalaxy and UserMenu
- Modal provides consistent UX with proper confirmation messaging
- Deletion follows write-through cache pattern: ATproto first, then SurrealDB

**SurrealDB RecordId Fixes:**
- Fixed SELECT query to use type::thing($table, $recordId) for UUID-based RecordIds
- Fixed DELETE query to use type::thing() instead of db.delete() to handle dashes in UUIDs
- Without type::thing(), SurrealDB interprets dashes as subtraction operators

**Testing & Documentation:**
- Added comprehensive Magnitude tests for delete functionality (galaxy view and debug panel)
- Updated CLAUDE.md with complete testing workflow documentation
- Added pre-commit checklist requiring database verification and test execution
- Documented PlaywrightMCP manual testing process before Magnitude test writing

**Database Setup:**
- Configured docker-compose.yml to use environment variables for credentials
- Updated namespace/database to match .env configuration (ponderants/main)

**File Changes:**
- app/api/nodes/[id]/route.ts: Fixed RecordId query patterns (SELECT and DELETE)
- components/DeleteNodeModal.tsx: New shared modal component
- components/ThoughtGalaxy.tsx: Uses shared DeleteNodeModal
- components/UserMenu.tsx: Replaced browser confirm() with shared DeleteNodeModal
- tests/magnitude/03-delete-node.mag.ts: Added debug panel delete test
- AGENTS.md: Added testing workflow and pre-commit checklist documentation
- docker-compose.yml: Environment variable configuration

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

components/DeleteNodeModal.tsx

@@ -0,0 +1,58 @@
+'use client';
+
+import { Modal, Stack, Text, Group, Button } from '@mantine/core';
+import { IconTrash } from '@tabler/icons-react';
+
+interface DeleteNodeModalProps {
+  opened: boolean;
+  onClose: () => void;
+  onConfirm: () => void;
+  nodeTitle: string | null;
+  isDeleting: boolean;
+}
+
+export function DeleteNodeModal({
+  opened,
+  onClose,
+  onConfirm,
+  nodeTitle,
+  isDeleting,
+}: DeleteNodeModalProps) {
+  return (
+    <Modal
+      opened={opened}
+      onClose={onClose}
+      title="Delete Node"
+      centered
+      zIndex={1001}
+    >
+      <Stack gap="md">
+        <Text>
+          Are you sure you want to delete &quot;{nodeTitle}&quot;? This will:
+        </Text>
+        <Stack gap="xs" ml="md">
+          <Text size="sm">• Remove the post from Bluesky</Text>
+          <Text size="sm">• Delete the node from your galaxy</Text>
+          <Text size="sm" fw={600} c="red">This action cannot be undone.</Text>
+        </Stack>
+        <Group justify="flex-end" gap="sm">
+          <Button
+            variant="subtle"
+            onClick={onClose}
+            disabled={isDeleting}
+          >
+            Cancel
+          </Button>
+          <Button
+            color="red"
+            onClick={onConfirm}
+            loading={isDeleting}
+            leftSection={<IconTrash size={16} />}
+          >
+            Delete Permanently
+          </Button>
+        </Group>
+      </Stack>
+    </Modal>
+  );
+}