feat(connector): add Airtable, PagerDuty, Twilio, and Asana connectors (#103, #99, #96, #116)

Implements eight connector actions across four services:
- airtable/list, airtable/create_record
- pagerduty/create_incident, pagerduty/resolve
- twilio/sms, twilio/call
- asana/create_task, asana/search

All connectors follow established patterns: dual credential shape
(map[string]string + map[string]any), url.PathEscape on user-supplied
path segments, io.LimitReader on response bodies, and httptest.Server
injection via baseURL for unit testing.

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

Author: 2 people

packages/engine/internal/connector/airtable.go

@@ -0,0 +1,202 @@
+package connector
+
+import (
+	"bytes"
+	"context"
+	"encoding/json"
+	"fmt"
+	"io"
+	"net/http"
+	"net/url"
+)
+
+const airtableBaseURL = "https://api.airtable.com/v0"
+
+// AirtableListConnector lists records from an Airtable table.
+type AirtableListConnector struct {
+	Client  *http.Client
+	baseURL string // override for testing
+}
+
+func (c *AirtableListConnector) apiURL(path string) string {
+	base := c.baseURL
+	if base == "" {
+		base = airtableBaseURL
+	}
+	return base + path
+}
+
+func (c *AirtableListConnector) Execute(ctx context.Context, params map[string]any) (map[string]any, error) {
+	token, err := extractAirtableToken(params)
+	if err != nil {
+		return nil, fmt.Errorf("airtable/list: %w", err)
+	}
+
+	baseID, _ := params["base_id"].(string)
+	if baseID == "" {
+		return nil, fmt.Errorf("airtable/list: base_id is required")
+	}
+	tableID, _ := params["table_id"].(string)
+	if tableID == "" {
+		return nil, fmt.Errorf("airtable/list: table_id is required")
+	}
+
+	path := fmt.Sprintf("/%s/%s", url.PathEscape(baseID), url.PathEscape(tableID))
+	reqURL := c.apiURL(path)
+
+	q := url.Values{}
+	if maxRecords, ok := extractInt(params["max_records"]); ok && maxRecords > 0 {
+		q.Set("maxRecords", fmt.Sprintf("%d", maxRecords))
+	}
+	if formula, ok := params["filter_by_formula"].(string); ok && formula != "" {
+		q.Set("filterByFormula", formula)
+	}
+	if view, ok := params["view"].(string); ok && view != "" {
+		q.Set("view", view)
+	}
+	if cursor, ok := params["offset"].(string); ok && cursor != "" {
+		q.Set("offset", cursor)
+	}
+	if encoded := q.Encode(); encoded != "" {
+		reqURL += "?" + encoded
+	}
+
+	req, err := http.NewRequestWithContext(ctx, "GET", reqURL, nil)
+	if err != nil {
+		return nil, fmt.Errorf("airtable/list: creating request: %w", err)
+	}
+	req.Header.Set("Authorization", "Bearer "+token)
+
+	resp, err := httpClient(c.Client).Do(req)
+	if err != nil {
+		return nil, fmt.Errorf("airtable/list: %w", err)
+	}
+	defer resp.Body.Close()
+
+	respBody, err := io.ReadAll(io.LimitReader(resp.Body, DefaultMaxResponseBytes))
+	if err != nil {
+		return nil, fmt.Errorf("airtable/list: reading response: %w", err)
+	}
+
+	if resp.StatusCode != http.StatusOK {
+		return nil, fmt.Errorf("airtable/list: Airtable API returned %d: %s", resp.StatusCode, truncate(string(respBody), 500))
+	}
+
+	var result struct {
+		Records []any  `json:"records"`
+		Offset  string `json:"offset"`
+	}
+	if err := json.Unmarshal(respBody, &result); err != nil {
+		return nil, fmt.Errorf("airtable/list: parsing response: %w", err)
+	}
+
+	out := map[string]any{
+		"records": result.Records,
+		"count":   len(result.Records),
+	}
+	if result.Offset != "" {
+		out["offset"] = result.Offset
+	}
+	return out, nil
+}
+
+// AirtableCreateRecordConnector creates a record in an Airtable table.
+type AirtableCreateRecordConnector struct {
+	Client  *http.Client
+	baseURL string // override for testing
+}
+
+func (c *AirtableCreateRecordConnector) apiURL(path string) string {
+	base := c.baseURL
+	if base == "" {
+		base = airtableBaseURL
+	}
+	return base + path
+}
+
+func (c *AirtableCreateRecordConnector) Execute(ctx context.Context, params map[string]any) (map[string]any, error) {
+	token, err := extractAirtableToken(params)
+	if err != nil {
+		return nil, fmt.Errorf("airtable/create_record: %w", err)
+	}
+
+	baseID, _ := params["base_id"].(string)
+	if baseID == "" {
+		return nil, fmt.Errorf("airtable/create_record: base_id is required")
+	}
+	tableID, _ := params["table_id"].(string)
+	if tableID == "" {
+		return nil, fmt.Errorf("airtable/create_record: table_id is required")
+	}
+
+	fields, _ := params["fields"].(map[string]any)
+	if fields == nil {
+		fields = map[string]any{}
+	}
+
+	body := map[string]any{"fields": fields}
+	reqJSON, err := json.Marshal(body)
+	if err != nil {
+		return nil, fmt.Errorf("airtable/create_record: marshaling request: %w", err)
+	}
+
+	path := fmt.Sprintf("/%s/%s", url.PathEscape(baseID), url.PathEscape(tableID))
+	req, err := http.NewRequestWithContext(ctx, "POST", c.apiURL(path), bytes.NewReader(reqJSON))
+	if err != nil {
+		return nil, fmt.Errorf("airtable/create_record: creating request: %w", err)
+	}
+	req.Header.Set("Authorization", "Bearer "+token)
+	req.Header.Set("Content-Type", "application/json")
+
+	resp, err := httpClient(c.Client).Do(req)
+	if err != nil {
+		return nil, fmt.Errorf("airtable/create_record: %w", err)
+	}
+	defer resp.Body.Close()
+
+	respBody, err := io.ReadAll(io.LimitReader(resp.Body, DefaultMaxResponseBytes))
+	if err != nil {
+		return nil, fmt.Errorf("airtable/create_record: reading response: %w", err)
+	}
+
+	if resp.StatusCode != http.StatusOK {
+		return nil, fmt.Errorf("airtable/create_record: Airtable API returned %d: %s", resp.StatusCode, truncate(string(respBody), 500))
+	}
+
+	var record struct {
+		ID          string         `json:"id"`
+		CreatedTime string         `json:"createdTime"`
+		Fields      map[string]any `json:"fields"`
+	}
+	if err := json.Unmarshal(respBody, &record); err != nil {
+		return nil, fmt.Errorf("airtable/create_record: parsing response: %w", err)
+	}
+
+	return map[string]any{
+		"id":           record.ID,
+		"created_time": record.CreatedTime,
+		"fields":       record.Fields,
+	}, nil
+}
+
+func extractAirtableToken(params map[string]any) (string, error) {
+	raw, ok := params["_credential"]
+	if !ok || raw == nil {
+		return "", fmt.Errorf("credential is required")
+	}
+	delete(params, "_credential")
+
+	var token string
+	switch cred := raw.(type) {
+	case map[string]string:
+		token = cred["token"]
+	case map[string]any:
+		token, _ = cred["token"].(string)
+	default:
+		return "", fmt.Errorf("credential is required")
+	}
+	if token == "" {
+		return "", fmt.Errorf("credential must contain a 'token' field")
+	}
+	return token, nil
+}