fix: rebase onto main, fix SQLite concurrency, lint clean

- Add busy_timeout PRAGMA and MaxOpenConns(1) for SQLite stability
- Use per-test temp DB in handler tests to prevent state leaks
- Pre-allocate migrations slice (prealloc lint)
- Remove invalid linter names (wsl_v5, noinlineerr) from .golangci.yml
- Remove unused //nolint:gosec directives
- Replace context.Background() with t.Context() in tests
- Use goimports formatting for all files
- All make check passes with zero failures

cmd/chat-cli/api/client.go

@@ -15,8 +15,8 @@ import (
 )
 
 const (
-	httpTimeout     = 30 * time.Second
-	pollExtraTime   = 5
+	httpTimeout      = 30 * time.Second
+	pollExtraTime    = 5
 	httpErrThreshold = 400
 )
 
@@ -125,7 +125,7 @@ func (c *Client) PollMessages(
 
 	req.Header.Set("Authorization", "Bearer "+c.Token)
 
-	resp, err := client.Do(req) //nolint:gosec // URL built from trusted BaseURL + hardcoded path
+	resp, err := client.Do(req)
 	if err != nil {
 		return nil, err
 	}
@@ -272,7 +272,7 @@ func (c *Client) do(
 		)
 	}
 
-	resp, err := c.HTTPClient.Do(req) //nolint:gosec // URL built from trusted BaseURL + hardcoded path
+	resp, err := c.HTTPClient.Do(req)
 	if err != nil {
 		return nil, fmt.Errorf("http: %w", err)
 	}