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/session/attempts.go

@@ -1,26 +0,0 @@
-// internal/session/attempts.go
-package session
-
-import iexec "github.com/mathiasbq/supervisor/internal/exec"
-
-// AttemptsFrom converts exec.AttemptRecord slice to session.Attempt slice
-// for writing into a session JSONL entry.
-func AttemptsFrom(records []iexec.AttemptRecord) []Attempt {
-	if len(records) == 0 {
-		return nil
-	}
-	out := make([]Attempt, len(records))
-	for i, r := range records {
-		out[i] = Attempt{
-			Attempt:    i + 1,
-			Model:      r.Model,
-			Tier:       r.Tier,
-			DurationMs: r.DurationMs,
-			WarmStart:  r.WarmStart,
-			Verdict:    r.Verdict,
-			Feedback:   r.Feedback,
-			Verified:   r.Verdict == "accept",
-		}
-	}
-	return out
-}

internal/session/attempts_test.go

@@ -1,37 +0,0 @@
-package session_test
-
-import (
-	"testing"
-
-	"github.com/mathiasbq/supervisor/internal/exec"
-	"github.com/mathiasbq/supervisor/internal/session"
-	"github.com/stretchr/testify/assert"
-	"github.com/stretchr/testify/require"
-)
-
-func TestAttemptsFromEmpty(t *testing.T) {
-	result := session.AttemptsFrom(nil)
-	assert.Empty(t, result)
-}
-
-func TestAttemptsFromSetsIndex(t *testing.T) {
-	records := []exec.AttemptRecord{
-		{Model: "ollama/phi4", Tier: "local", DurationMs: 1200, WarmStart: true, Verdict: "escalate", Feedback: "too vague"},
-		{Model: "claude-sonnet-4-6", Tier: "subagent", DurationMs: 3400, WarmStart: false, Verdict: "accept"},
-	}
-	result := session.AttemptsFrom(records)
-	require.Len(t, result, 2)
-
-	assert.Equal(t, 1, result[0].Attempt)
-	assert.Equal(t, "ollama/phi4", result[0].Model)
-	assert.Equal(t, "local", result[0].Tier)
-	assert.Equal(t, int64(1200), result[0].DurationMs)
-	assert.True(t, result[0].WarmStart)
-	assert.Equal(t, "escalate", result[0].Verdict)
-	assert.Equal(t, "too vague", result[0].Feedback)
-	assert.False(t, result[0].Verified)
-
-	assert.Equal(t, 2, result[1].Attempt)
-	assert.Equal(t, "claude-sonnet-4-6", result[1].Model)
-	assert.True(t, result[1].Verified)
-}