fix(web): prevent narrow session tooltips

[techotaku39]

Summary

• size non-row hover tooltips to their intrinsic content width
• retain the existing 14rem maximum so detailed attention and schedule tooltips still wrap
• cover short localized tooltip copy with a regression test

Problem

Session attention indicators use an 8px dot as the containing block for an absolutely positioned tooltip. Non-row tooltips had only a maximum width, so their auto width could collapse to the narrow trigger. CJK copy such as 有新活动 then wrapped one character per line and appeared vertical.

Fix

Add Tailwind's w-max to non-row tooltip panels while keeping max-w-[14rem]. Short labels now use their max-content width, while longer rich tooltip content remains bounded and wraps normally. Row-spanning tooltips keep their existing sizing behavior.

Related: #940, #941

Test plan

• bun typecheck
• bun run test:web (158 files, 1298 tests)
• Regression test verifies localized non-row tooltips receive both w-max and max-w-[14rem]
• Manual browser check: hover an unread session dot and confirm 有新活动 renders horizontally

AI disclosure

AI-assisted implementation and PR drafting: OpenAI Codex (gpt-5.6-sol).

[github-actions]

Findings

• No findings.

Summary

• Review mode: initial
• Reviewed the full latest diff for web/src/components/HoverTooltip.tsx and web/src/components/HoverTooltip.test.tsx; no high-confidence correctness, security, regression, data loss, performance, or maintainability issues found in the added/modified lines.
• Residual risk: the new regression is class-level only; real browser layout behavior for CJK tooltip copy is not exercised by this review.

Testing

• Not run (automation)

HAPI Bot