Add a stale-issue/PR bot configuration

[Akatenvictor]

Problem / Context

With 300 new issues being created, an automated staleness policy will help keep the tracker healthy over time.

Proposed approach

Add a stale-bot config marking issues/PRs inactive after a defined period, with a grace period before closing.

Acceptance criteria

• Config added and dry-run tested
• Exempts labels like Stellar Wave/pinned from auto-closing if desired
• Documented in CONTRIBUTING.md

[drips-wave]

@Akatenvictor This issue could not be added to the Stellar Wave Program because the per-repo points budget would be exceeded (25000 / 25000 points already used). The label has been automatically removed.

The budget resets at the end of each Wave. You can review the remaining budget for your repos on the Orgs & Repos page.

ℹ️ Learn more about points budgets

[drips-wave]

@Akatenvictor This issue could not be added to the Stellar Wave Program because the per-repo points budget would be exceeded (25000 / 25000 points already used). The label has been automatically removed.

The budget resets at the end of each Wave. You can review the remaining budget for your repos on the Orgs & Repos page.

ℹ️ Learn more about points budgets

[drips-wave]

@Akatenvictor This issue could not be added to the Stellar Wave Program because the per-repo points budget would be exceeded (25000 / 25000 points already used). The label has been automatically removed.

The budget resets at the end of each Wave. You can review the remaining budget for your repos on the Orgs & Repos page.

ℹ️ Learn more about points budgets

[drips-wave]

@Akatenvictor This issue could not be added to the Stellar Wave Program because the per-repo points budget would be exceeded (25000 / 25000 points already used). The label has been automatically removed.

The budget resets at the end of each Wave. You can review the remaining budget for your repos on the Orgs & Repos page.

ℹ️ Learn more about points budgets