docs: fix review resolution states, add human-side interactions

[selfcontained]

Summary

• tools.tsx: dispatch_review_resolve resolution options updated from fixed/ignored/wont_fix to fixed/dismissed (matching PR Fix extractHunkAroundLines bug for top-of-file hunks, add 19 tests #767's DB migration and MCP handler changes)
• agents.tsx: Documented that humans can now reply to threads, resolve items, and reopen feedback directly from the UI — both inline in the diff and from the Reviews sidebar tab
• tips.ts: Updated diff-review tip to reflect bidirectional interaction ("Both you and the agent can reply, resolve, or reopen items")

Deferred to next run

• Full Repo Tools deep-dive (tool handler descriptions vs docs summaries) — the tool list itself is accurate; this run focused on the resolution state drift from the recent diff
• dispatch_review_add_message body max reduced from 50,000 to 1,200 chars — the docs description doesn't mention the limit, and the tool's own schema describes it to agents directly

Test plan

• pnpm run format:write — clean
• pnpm run check — types pass
• No runtime behavior changes — docs-only PR

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