refactor: replace orchestrator/verifier chain with direct LiteLLM calls

Drop the three-layer Claude subprocess orchestration (local model →
Claude verifier → cloud escalation). Skills now call LiteLLM directly
and return plain text to Claude Code, which decides what to do with it.

- Delete executor, orchestrator, verifier, result, attempts packages
- Simplify LiteLLMExecutor: Run(Request)→Result becomes Complete(model,sys,user)→(string,int64,error)
- Replace ExecutorFn with CompleteFunc in all 6 skill configs
- Rewrite all skill handlers to call Complete and return {"text","model","duration_ms"}
- Simplify config/models: remove Verifier/LlamaSwapURL, add ModelFor
- Bump version to v0.5.0

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

internal/skills/trainer/handlers.go

@@ -7,7 +7,6 @@ import (
 	"fmt"
 	"time"
 
-	iexec "github.com/mathiasbq/supervisor/internal/exec"
 	"github.com/mathiasbq/supervisor/internal/session"
 )
 
@@ -28,7 +27,7 @@ func (s *Skill) Handle(ctx context.Context, tool string, args json.RawMessage) (
 	if a.SessionID == "" {
 		return nil, fmt.Errorf("session_id is required")
 	}
-	if s.cfg.ExecutorFn == nil {
+	if s.cfg.CompleteFunc == nil {
 		return nil, fmt.Errorf("no executor configured")
 	}
 
@@ -42,53 +41,47 @@ func (s *Skill) Handle(ctx context.Context, tool string, args json.RawMessage) (
 		return nil, fmt.Errorf("read session log: %w", err)
 	}
 
-	// ── Step 1: Reader agent ─────────────────────────────────────────────────
+	// ── Step 1: Reader ────────────────────────────────────────────────────────
 	history := session.FormatHistory(entries, "")
 	readerTask := fmt.Sprintf(
 		"role: reader\nsession_id: %s\nbrain_dir: %s\n\n%s",
 		a.SessionID, s.cfg.BrainDir, history,
 	)
-	readerResult, err := s.cfg.ExecutorFn(ctx, iexec.Request{
-		SkillPrompt: s.cfg.ReaderPrompt,
-		TaskPrompt:  readerTask,
-		Model:       model,
-		Tools:       "Read",
-	})
+	readerText, _, err := s.cfg.CompleteFunc(ctx, model, s.cfg.ReaderPrompt, readerTask)
 	if err != nil {
-		return nil, fmt.Errorf("reader agent: %w", err)
+		return nil, fmt.Errorf("reader: %w", err)
 	}
 
-	// ── Step 2: Writer agent (receives reader candidates) ────────────────────
+	// ── Step 2: Writer (receives reader output) ───────────────────────────────
 	t0 := time.Now()
 	writerTask := fmt.Sprintf(
-		"role: writer\nsession_id: %s\nbrain_dir: %s\n\nreader_summary: %s\nreader_candidates:\n%s",
-		a.SessionID, s.cfg.BrainDir, readerResult.Message, readerResult.RunnerOutput,
+		"role: writer\nsession_id: %s\nbrain_dir: %s\n\nreader_analysis:\n%s",
+		a.SessionID, s.cfg.BrainDir, readerText,
 	)
-	writerResult, err := s.cfg.ExecutorFn(ctx, iexec.Request{
-		SkillPrompt: s.cfg.WriterPrompt,
-		TaskPrompt:  writerTask,
-		Model:       model,
-		Tools:       "Read,Write",
-	})
+	writerText, dur, err := s.cfg.CompleteFunc(ctx, model, s.cfg.WriterPrompt, writerTask)
 	if err != nil {
-		return nil, fmt.Errorf("writer agent: %w", err)
+		return nil, fmt.Errorf("writer: %w", err)
 	}
 
+	msg := writerText
+	if len(msg) > 200 {
+		msg = msg[:200]
+	}
 	_ = session.Append(s.cfg.SessionsDir, a.SessionID, session.Entry{
 		SessionID:   a.SessionID,
 		Timestamp:   time.Now(),
 		Skill:       "trainer",
 		Phase:       "trainer",
-		Attempts:    session.AttemptsFrom(writerResult.Attempts),
-		FinalStatus: writerResult.Status,
-		ModelUsed:   writerResult.ModelUsed,
+		FinalStatus: "ok",
+		ModelUsed:   model,
 		DurationMs:  time.Since(t0).Milliseconds(),
-		Message:     writerResult.Message,
+		Message:     msg,
 	})
 
-	b, err := json.Marshal(writerResult)
-	if err != nil {
-		return nil, fmt.Errorf("marshal result: %w", err)
-	}
-	return b, nil
+	return json.Marshal(map[string]any{
+		"reader_analysis": readerText,
+		"writer_output":   writerText,
+		"model":           model,
+		"duration_ms":     dur,
+	})
 }