Added branches support

[sunil-lakshman]

• Feat
  • Branch support
    • Added Branch model with Create, CreateAsync, Fetch, FetchAsync, Delete, DeleteAsync, and Query operations
    • Added BranchModel and BranchAliasModel with System.Text.Json serialization
    • Stack.Branch(uid?) accessor follows the same pattern as other stack resources
    • Added unit tests (BranchTest) covering resource path, SDK guard conditions, and query parameter construction
    • Added integration tests (Contentstack005_BranchTest) covering CRUD lifecycle, query with pagination, SDK validation errors, and API error scenarios
  • Webhook migration to System.Text.Json
    • Migrated WebhookModel to use System.Text.Json attributes
  • Workflow migration to System.Text.Json
    • Migrated WorkflowModel to use System.Text.Json attributes

[github-actions]

🔒 Security Scan Results

ℹ️ Note: Only vulnerabilities with available fixes (upgrades or patches) are counted toward thresholds.

Check Type	Count (with fixes)	Without fixes	Threshold	Result
🔴 Critical Severity	0	0	10	✅ Passed
🟠 High Severity	0	0	25	✅ Passed
🟡 Medium Severity	0	0	500	✅ Passed
🔵 Low Severity	0	0	1000	✅ Passed

⏱️ SLA Breach Summary

✅ No SLA breaches detected. All vulnerabilities are within acceptable time thresholds.

Severity	Breaches (with fixes)	Breaches (no fixes)	SLA Threshold (with/no fixes)	Status
🔴 Critical	0	0	15 / 30 days	✅ Passed
🟠 High	0	0	30 / 120 days	✅ Passed
🟡 Medium	0	0	90 / 365 days	✅ Passed
🔵 Low	0	0	180 / 365 days	✅ Passed

✅ BUILD PASSED - All security checks passed

[reeshika-h]

lgtm

[OMpawar-21]

LGTM