improve reasoning toggle tests and refactor model capability checks

src/db/attachments.js

@@ -0,0 +1,31 @@
+export function initializeAttachments(db) {
+    db.exec(`
+        CREATE TABLE IF NOT EXISTS attachments (
+            id TEXT PRIMARY KEY, username TEXT NOT NULL REFERENCES users(username) ON DELETE CASCADE ON UPDATE CASCADE,
+            original_name TEXT NOT NULL, storage_key TEXT NOT NULL UNIQUE, mime_type TEXT NOT NULL,
+            size_bytes INTEGER NOT NULL, width INTEGER NOT NULL, height INTEGER NOT NULL,
+            status TEXT NOT NULL DEFAULT 'temporary' CHECK(status IN ('temporary','attached')),
+            created_at TEXT NOT NULL DEFAULT CURRENT_TIMESTAMP,
+            vision_model TEXT, vision_analysis TEXT, vision_analyzed_at TEXT
+        );
+        CREATE TABLE IF NOT EXISTS message_attachments (
+            message_id INTEGER NOT NULL REFERENCES chat_messages(id) ON DELETE CASCADE,
+            attachment_id TEXT NOT NULL REFERENCES attachments(id) ON DELETE CASCADE,
+            position INTEGER NOT NULL DEFAULT 0, PRIMARY KEY(message_id, attachment_id)
+        );
+        CREATE INDEX IF NOT EXISTS attachment_references ON message_attachments(attachment_id);
+        CREATE TABLE IF NOT EXISTS upload_deletions (storage_key TEXT PRIMARY KEY);
+        CREATE TRIGGER IF NOT EXISTS release_message_attachment AFTER DELETE ON message_attachments
+        BEGIN
+            DELETE FROM attachments WHERE id = OLD.attachment_id AND status = 'attached'
+            AND NOT EXISTS (SELECT 1 FROM message_attachments WHERE attachment_id = OLD.attachment_id);
+        END;
+        CREATE TRIGGER IF NOT EXISTS queue_attachment_file_delete AFTER DELETE ON attachments
+        BEGIN INSERT OR IGNORE INTO upload_deletions(storage_key) VALUES(OLD.storage_key); END;
+    `);
+}
+
+export const attachmentMetadata = (row) => ({
+    id: row.id, type: "image", originalName: row.original_name, mimeType: row.mime_type,
+    sizeBytes: row.size_bytes, width: row.width, height: row.height
+});