Improve large balance amount display

[crossagent-production-app]

Fixes #40

Summary

• Added a shared frontend balance formatter that keeps existing decimal scaling but renders large fund amounts with Million/Billion/Trillion suffixes and bounded precision.
• Applied the formatter to account, contract, token, transaction, transfer, and holder balance/value surfaces.

Verification

• npm test -- --runTestsByPath src/__tests__/utils/text.test.ts --runInBand
• E2E_BASE_URL=http://localhost:3210 ./node_modules/.bin/playwright test tmp/task_2ce70c44022b4334/account-balance-format.e2e.spec.ts --reporter=line
• ./node_modules/.bin/playwright test tmp/task_2ce70c44022b4334/pr-evidence-render.e2e.spec.ts --reporter=line

Delivery Evidence Summary

Change:

Large balance/value fields now render in compact human-readable units, for example 12.0648 Million, 2.5597 Million, and 9.5051 Million on the reported account card, while small and ordinary values keep readable decimal precision.

Objective Evidence:

• Unit formatter coverage passed: npm test -- --runTestsByPath src/__tests__/utils/text.test.ts --runInBand (29 tests passed).
• Product browser validation passed: E2E_BASE_URL=http://localhost:3210 ./node_modules/.bin/playwright test tmp/task_2ce70c44022b4334/account-balance-format.e2e.spec.ts --reporter=line (1 Playwright test passed).
• PR evidence rendering check passed: ./node_modules/.bin/playwright test tmp/task_2ce70c44022b4334/pr-evidence-render.e2e.spec.ts --reporter=line (1 Playwright test passed).

Visual Evidence:

Source Screenshot Match: matched the reported /sub/account/49VYuGkjdmZprGpb4jU313RdSffxSVHixojzmafdFYGpVYXb page and same balance card/table section with anchors Account, Total Balance, Transferrable, Locked, Vested, Reserved, and the Extrinsics tab. Live API data now returns a non-zero Vested value, so that field differs from the first source screenshot but the matched product surface is the same.

Reviewer:

@repo Intake Reviewer

Risks / Not Covered:

• npm run prettier -- --check ... invokes the repository's app-wide Prettier script and still fails on existing formatting drift across many untouched files; this PR did not reformat the whole frontend.
• Visual proof used the local Next.js frontend against the live Heima API because the reported production/test explorer can be auth-gated or flaky in headless sessions.

[vercel]

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Project	Deployment	Actions	Updated (UTC)
subscan-essentials	Ready	Preview, Comment	May 25, 2026 7:26pm
subscan-essentials-ui-react	Ready	Preview, Comment	May 25, 2026 7:26pm

[crossagent-production-app]

Delivery Evidence Summary

Change:

• Updated compact native balances on the reported account page to include the chain token symbol, e.g. Million HEI instead of only Million.
• Kept the shared large-number formatter and appended native token labels at the account balance display layer.

Objective Evidence:

• npm test -- --runTestsByPath src/__tests__/utils/text.test.ts --runInBand exit code 0: Formatter unit coverage passed after the token-symbol display update.
• E2E_BASE_URL=http://localhost:3210 ./node_modules/.bin/playwright test tmp/task_2ce70c44022b4334/account-balance-format.e2e.spec.ts --reporter=line exit code 0: Browser E2E passed with exact Million HEI assertions on the reported account balance surface.
• git diff --check && git status --short && git diff --stat exit code 0: Diff check passed; only committed PR changes remain in the delivery branch after cleanup.

Visual Evidence:

• 
• Source Screenshot Match: same product surface as the issue screenshot, matching /sub/account/49VYuGkjdmZprGpb4jU313RdSffxSVHixojzmafdFYGpVYXb account page balance card/table anchors: Account, Total Balance, Transferrable, Locked, Vested, Reserved, and Extrinsics.
• The visible balance values now include the token symbol, including 12.0648 Million HEI, 2.5597 Million HEI, 9.5051 Million HEI, 18.7299 Million HEI, and 0 HEI.

Reviewer:

• @repo Intake Reviewer

Risks / Not Covered:

• The repository app-wide Prettier script still has existing formatting drift outside this PR scope; this PR did not reformat the whole frontend.
• Visual proof used the local Next.js frontend against the live Heima API because the reported production/test explorer can be auth-gated or flaky in headless sessions.

Generated at: 2026-05-25T19:41:22Z

[YoshiyukiSakura]

this is not good enough，we want “Million HEI” not only "Million"