Project refactor, add anthropic API support

- Split pkg/cli/cmd.go into new pkg/cmd package
- Split pkg/cli/functions.go into pkg/lmcli/tools package
- Refactor pkg/cli/openai.go to pkg/lmcli/provider/openai

Other changes:

- Made models configurable
- Slight config reorganization

pkg/cmd/view.go

@@ -0,0 +1,45 @@
+package cmd
+
+import (
+	"fmt"
+
+	cmdutil "git.mlow.ca/mlow/lmcli/pkg/cmd/util"
+	"git.mlow.ca/mlow/lmcli/pkg/lmcli"
+	"github.com/spf13/cobra"
+)
+
+func ViewCmd(ctx *lmcli.Context) *cobra.Command {
+	cmd := &cobra.Command{
+		Use:   "view <conversation>",
+		Short: "View messages in a conversation",
+		Long:  `Finds a conversation by its short name and displays its contents.`,
+		Args: func(cmd *cobra.Command, args []string) error {
+			argCount := 1
+			if err := cobra.MinimumNArgs(argCount)(cmd, args); err != nil {
+				return err
+			}
+			return nil
+		},
+		RunE: func(cmd *cobra.Command, args []string)  error {
+			shortName := args[0]
+			conversation := cmdutil.LookupConversation(ctx, shortName)
+
+			messages, err := ctx.Store.Messages(conversation)
+			if err != nil {
+				return fmt.Errorf("Could not retrieve messages for conversation: %s", conversation.Title)
+			}
+
+			cmdutil.RenderConversation(ctx, messages, false)
+			return nil
+		},
+		ValidArgsFunction: func(cmd *cobra.Command, args []string, toComplete string) ([]string, cobra.ShellCompDirective) {
+			compMode := cobra.ShellCompDirectiveNoFileComp
+			if len(args) != 0 {
+				return nil, compMode
+			}
+			return ctx.Store.ConversationShortNameCompletions(toComplete), compMode
+		},
+	}
+
+	return cmd
+}