fix(security): replace real AWS account ID with placeholder

The production AWS account ID was committed in four tracked files (a
sender.go doc comment, email template test fixtures, frontend
settings-accounts test fixtures, and a known_issues UX review doc),
violating the .gitallowed policy that only deliberate placeholders may
appear in the repo. Replace every occurrence with the allowlisted
placeholder 123456789012.

No literal-absence regression test is added because such a test would
re-embed the very ID it guards against; the git-secrets pre-commit/CI
gate remains the enforcement point. The gate hole (bare 12-digit IDs in
string labels and comments escape the registered key=value pattern) and
the history-scrubbing decision are documented on the tracking issue.

Verified: go build ./..., go test ./internal/email/... (335 passed),
npx jest settings-accounts.test.ts (80 passed), git grep confirms zero
remaining occurrences.

Closes #1167

Author: cristim

frontend/src/__tests__/settings-accounts.test.ts

@@ -1237,28 +1237,28 @@ describe('Account overrides modal', () => {
 
   test('Overrides button opens an account-scoped modal whose title binds to the account', async () => {
     (api.listAccounts as jest.Mock).mockResolvedValue([
-      { id: 'acc-1', name: 'AWS Prod', provider: 'aws', external_id: '540659244915', enabled: true },
+      { id: 'acc-1', name: 'AWS Prod', provider: 'aws', external_id: '123456789012', enabled: true },
     ]);
     (api.listAccountServiceOverrides as jest.Mock).mockResolvedValue([
       { id: 'o1', account_id: 'acc-1', provider: 'aws', service: 'ec2', payment: 'all-upfront' },
     ]);
 
     await loadAccountsForProvider('aws');
     const btn = document.querySelector(
-      `button[aria-label="Service overrides for AWS Prod (540659244915)"]`,
+      `button[aria-label="Service overrides for AWS Prod (123456789012)"]`,
     ) as HTMLButtonElement;
     btn.click();
     await new Promise(r => setTimeout(r, 0));
 
     const modal = document.getElementById('account-overrides-modal') as HTMLElement;
     expect(modal.classList.contains('hidden')).toBe(false);
     const title = document.getElementById('account-overrides-modal-title') as HTMLElement;
-    expect(title.textContent).toBe('Service overrides for AWS Prod (540659244915)');
+    expect(title.textContent).toBe('Service overrides for AWS Prod (123456789012)');
   });
 
   test('switching accounts swaps the modal title; only one account context is active at a time', async () => {
     (api.listAccounts as jest.Mock).mockResolvedValue([
-      { id: 'acc-a', name: 'AWS Prod',  provider: 'aws', external_id: '540659244915', enabled: true },
+      { id: 'acc-a', name: 'AWS Prod',  provider: 'aws', external_id: '123456789012', enabled: true },
       { id: 'acc-b', name: 'CUDly host', provider: 'aws', external_id: '909626172446', enabled: true },
     ]);
     (api.listAccountServiceOverrides as jest.Mock).mockResolvedValue([]);
@@ -1268,7 +1268,7 @@ describe('Account overrides modal', () => {
 
     // Click Overrides on Account A.
     (document.querySelector(
-      `button[aria-label="Service overrides for AWS Prod (540659244915)"]`,
+      `button[aria-label="Service overrides for AWS Prod (123456789012)"]`,
     ) as HTMLButtonElement).click();
     await new Promise(r => setTimeout(r, 0));
     expect(titleEl.textContent).toContain('AWS Prod');

internal/email/sender.go

@@ -504,7 +504,7 @@ type RecommendationSummary struct {
 	// "$0" so a no-upfront payment option visibly shows that fact.
 	UpfrontCost float64
 	// AccountLabel is a friendly per-rec account identifier (e.g.
-	// "AWS 540659244915 (acme-prod)"). Empty omits the line.
+	// "AWS 123456789012 (acme-prod)"). Empty omits the line.
 	AccountLabel string
 }
 

internal/email/template_renderers_test.go

@@ -269,7 +269,7 @@ func TestRenderPurchaseApprovalRequestEmail_NewContextFields_Issue287(t *testing
 		Recommendations: []RecommendationSummary{{
 			Service: "ec2", ResourceType: "m5.large", Region: "us-east-1",
 			Count: 8, Term: 3, Payment: "all-upfront", UpfrontCost: 1234.56,
-			MonthlySavings: 58.0, AccountLabel: "AWS 540659244915",
+			MonthlySavings: 58.0, AccountLabel: "AWS 123456789012",
 		}},
 	}
 
@@ -280,7 +280,7 @@ func TestRenderPurchaseApprovalRequestEmail_NewContextFields_Issue287(t *testing
 	assert.Contains(t, body, "Term: 3yr")
 	assert.Contains(t, body, "Payment: all-upfront")
 	assert.Contains(t, body, "Upfront: $1234.56")
-	assert.Contains(t, body, "Account: AWS 540659244915")
+	assert.Contains(t, body, "Account: AWS 123456789012")
 
 	// Requested-by header.
 	assert.Contains(t, body, "Cristi M")
@@ -318,7 +318,7 @@ func TestRenderPurchaseApprovalRequestEmailHTML_Issue287(t *testing.T) {
 		Recommendations: []RecommendationSummary{{
 			Service: "ec2", ResourceType: "m5.large", Region: "us-east-1",
 			Count: 8, Term: 3, Payment: "all-upfront", UpfrontCost: 1234.56,
-			MonthlySavings: 58.0, AccountLabel: "AWS 540659244915",
+			MonthlySavings: 58.0, AccountLabel: "AWS 123456789012",
 		}},
 	}
 

known_issues/23_ux_review_2026_04_22.md

@@ -507,7 +507,7 @@
 
 #### MEDIUM: Per-provider Accounts sections render as inline text rows — need a table
 
-**Evidence:** `AWS personal (540659244915) Edit Test Credentials Overrides Delete` is a single text-flow line. Hard to scan.
+**Evidence:** `AWS personal (123456789012) Edit Test Credentials Overrides Delete` is a single text-flow line. Hard to scan.
 
 **Recommended fix:** Convert to a table: `Name | ID | Status | Actions`.