docs: update frameworks comparison with v4.0 features

[bpamiri]

Summary

Updates docs/wheels-vs-frameworks.md to reflect the six framework features merged in April 2026:

• Bulk operations (#2101) — `insertAll`/`upsertAll` with per-DB UPSERT for all 7 adapters
• Polymorphic associations (#2104) — `belongsTo(polymorphic=true)` and `hasMany(as=)`
• Advisory locks + SELECT FOR UPDATE (#2103)
• Auto-migrations from models (#2102) — `AutoMigrator` schema diff
• HTTP test client (#2099) — fluent `visit().assertOk().assertSee()`
• Parallel test execution (#2100) — `ParallelRunner` with cfthread

Changes:

• ORM table: adds polymorphic associations, bulk insert/upsert, advisory locks, pessimistic locking rows
• Migrations section: documents `AutoMigrator` alongside `makemigrations` parity
• Testing section: documents `TestClient` (HTTP integration) and `ParallelRunner` (parallel execution)
• "Where Wheels Leads": adds 6 new items
• "Where Wheels Trails": removes the 6 closed gaps; remaining items are ecosystem size, community, browser testing, asset pipeline, WebSocket (a deliberate design choice given CFML's request-response model)
• New "Recently Closed Gaps (April 2026)" section with PR references

Test plan

• Markdown renders correctly on GitHub
• All PR references link to merged PRs
• Tables remain aligned and readable

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