feat(web): give lineage subagent hovers the thread hover card

[maria-rcks]

Subagent hovers in Lineage showed label/value rows and wrapping activity text. They now reuse the sidebar thread hover's glass shell, title spacing, and compact provider/model row, with sidebar-style status, elapsed time, and a single middle-truncated detail line. The timeline uses the same content; existing result selection, differing-project/workspace metadata, and triggers are preserved.

Verified web typecheck, web lint (existing warnings, no errors), and all 72 existing timeline and relationship tests on Blacksmith. Inspected Lineage in dark/light and the timeline hover against a snapshot of real provider data. The sampled agent has completed, so these captures show its result; a live running-provider transition remains unverified.

before, dark:

after, dark:

before, light:

after, light:

existing sidebar reference:

Written by gpt-6-astra (Codex) in T3 Code

[macroscopeapp]

Approvability

Verdict: Not approved

Macroscope's review found this PR not approvable — This PR introduces a new shared hover-card component and changes existing lineage and timeline subagent hovers with provider, status, elapsed-time, metadata, and preview behavior. The change is isolated to web UI and has no schema or infrastructure impact, but its always-active user-facing behavior across multiple production surfaces warrants human review.

^{You can add or adjust custom eligibility rules. Learn more.}