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/edit.go

@@ -3,9 +3,9 @@ package cmd
 import (
 	"fmt"
 
+	"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"
 )
 
@@ -53,10 +53,10 @@ func EditCmd(ctx *lmcli.Context) *cobra.Command {
 
 			role, _ := cmd.Flags().GetString("role")
 			if role != "" {
-				if role != string(model.MessageRoleUser) && role != string(model.MessageRoleAssistant) {
+				if role != string(api.MessageRoleUser) && role != string(api.MessageRoleAssistant) {
 					return fmt.Errorf("Invalid role specified. Please use 'user' or 'assistant'.")
 				}
-				toEdit.Role = model.MessageRole(role)
+				toEdit.Role = api.MessageRole(role)
 			}
 
 			// Update the message in-place