feat(tools): implement CRUD operations for thoughts and projects

* Add tools for creating, retrieving, updating, and deleting thoughts.
* Implement project management tools for creating and listing projects.
* Introduce linking functionality between thoughts.
* Add search and recall capabilities for thoughts based on semantic queries.
* Implement statistics and summarization tools for thought analysis.
* Create database migrations for thoughts, projects, and links.
* Add helper functions for UUID parsing and project resolution.

internal/config/loader_test.go

@@ -0,0 +1,71 @@
+package config
+
+import (
+	"os"
+	"path/filepath"
+	"testing"
+)
+
+func TestResolvePathPrecedence(t *testing.T) {
+	t.Setenv("OB1_CONFIG", "/tmp/from-env.yaml")
+
+	if got := ResolvePath("/tmp/explicit.yaml"); got != "/tmp/explicit.yaml" {
+		t.Fatalf("ResolvePath explicit = %q, want %q", got, "/tmp/explicit.yaml")
+	}
+
+	if got := ResolvePath(""); got != "/tmp/from-env.yaml" {
+		t.Fatalf("ResolvePath env = %q, want %q", got, "/tmp/from-env.yaml")
+	}
+}
+
+func TestLoadAppliesEnvOverrides(t *testing.T) {
+	configPath := filepath.Join(t.TempDir(), "test.yaml")
+	if err := os.WriteFile(configPath, []byte(`
+server:
+  port: 8080
+mcp:
+  path: "/mcp"
+auth:
+  keys:
+    - id: "test"
+      value: "secret"
+database:
+  url: "postgres://from-file"
+ai:
+  provider: "litellm"
+  embeddings:
+    dimensions: 1536
+  litellm:
+    base_url: "http://localhost:4000/v1"
+    api_key: "file-key"
+search:
+  default_limit: 10
+  max_limit: 50
+logging:
+  level: "info"
+`), 0o600); err != nil {
+		t.Fatalf("write config: %v", err)
+	}
+
+	t.Setenv("OB1_DATABASE_URL", "postgres://from-env")
+	t.Setenv("OB1_LITELLM_API_KEY", "env-key")
+	t.Setenv("OB1_SERVER_PORT", "9090")
+
+	cfg, loadedFrom, err := Load(configPath)
+	if err != nil {
+		t.Fatalf("Load() error = %v", err)
+	}
+
+	if loadedFrom != configPath {
+		t.Fatalf("loadedFrom = %q, want %q", loadedFrom, configPath)
+	}
+	if cfg.Database.URL != "postgres://from-env" {
+		t.Fatalf("database url = %q, want env override", cfg.Database.URL)
+	}
+	if cfg.AI.LiteLLM.APIKey != "env-key" {
+		t.Fatalf("litellm api key = %q, want env override", cfg.AI.LiteLLM.APIKey)
+	}
+	if cfg.Server.Port != 9090 {
+		t.Fatalf("server port = %d, want 9090", cfg.Server.Port)
+	}
+}