Package restructure and API changes, several fixes

- More emphasis on `api` package. It now holds database model structs
  from `lmcli/models` (which is now gone) as well as the tool spec,
  call, and result types. `tools.Tool` is now `api.ToolSpec`.
  `api.ChatCompletionClient` was renamed to
  `api.ChatCompletionProvider`.

- Change ChatCompletion interface and implementations to no longer do
  automatic tool call recursion - they simply return a ToolCall message
  which the caller can decide what to do with (e.g. prompt for user
  confirmation before executing)

- `api.ChatCompletionProvider` functions have had their ReplyCallback
  parameter removed, as now they only return a single reply.

- Added a top-level `agent` package, moved the current built-in tools
  implementations under `agent/toolbox`. `tools.ExecuteToolCalls` is now
  `agent.ExecuteToolCalls`.

- Fixed request context handling in openai, google, ollama (use
  `NewRequestWithContext`), cleaned up request cancellation in TUI

- Fix tool call tui persistence bug (we were skipping message with empty
  content)

- Now handle tool calling from TUI layer

TODO:
- Prompt users before executing tool calls
- Automatically send tool results to the model (or make this toggleable)

pkg/cmd/continue.go

@@ -4,9 +4,9 @@ import (
 	"fmt"
 	"strings"
 
+	"git.mlow.ca/mlow/lmcli/pkg/api"
 	cmdutil "git.mlow.ca/mlow/lmcli/pkg/cmd/util"
 	"git.mlow.ca/mlow/lmcli/pkg/lmcli"
-	"git.mlow.ca/mlow/lmcli/pkg/lmcli/model"
 	"github.com/spf13/cobra"
 )
 
@@ -36,7 +36,7 @@ func ContinueCmd(ctx *lmcli.Context) *cobra.Command {
 			}
 
 			lastMessage := &messages[len(messages)-1]
-			if lastMessage.Role != model.MessageRoleAssistant {
+			if lastMessage.Role != api.MessageRoleAssistant {
 				return fmt.Errorf("the last message in the conversation is not an assistant message")
 			}
 
@@ -50,7 +50,7 @@ func ContinueCmd(ctx *lmcli.Context) *cobra.Command {
 			}
 
 			// Append the new response to the original message
-			lastMessage.Content += strings.TrimRight(continuedOutput, "\n\t ")
+			lastMessage.Content += strings.TrimRight(continuedOutput.Content, "\n\t ")
 
 			// Update the original message
 			err = ctx.Store.UpdateMessage(lastMessage)