[1135] Add Vue file size warning

[Chris0Jeky]

Summary

• add a warn-level core ESLint max-lines guard for Vue SFCs at 700 nonblank, noncomment lines
• explicitly allowlist the nine current high-cohesion exceptions with local rationale comments
• keep the existing --max-warnings=20 budget unchanged and scope the rule away from TypeScript

Proof

• synthetic short SFC: no max-lines warning
• synthetic 705-line unlisted SFC: one max-lines warning
• synthetic 701-line TypeScript control: no max-lines warning
• npm run lint (8 pre-existing warnings, 0 errors)
• npm run typecheck
• npm run build (known ineffective dynamic-import warning only)
• git diff --check

Refs #1135

No issue close or merge requested; this PR is intentionally left open for review.

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