refactor(provider-core): move the driver interface into provider-core

[juliusmarminge]

Every driver implements an interface that lived inside apps/server, so no driver could live in its own package.

This moves the driver contract into @t3tools/provider-core/server/*: the driver and instance records, the V2 adapter shape and its errors, selection transitions, the snapshot shape, the auth controller, the text-generation operations, maintenance capabilities, and ProviderDriverError. Server modules that implemented these keep their services and re-export the moved types. The adapter's Effect service key follows its new module path (an in-memory tag; nothing persists it).

No behavior change.

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Part of the provider-packages stack: #17282 → #17283 → #17284 → #17285 → #17286 → #17287 → #17288.

Done by Claude Opus 5.5 in Claude Code.

🤖 Generated with Claude Code

[github-actions]

Thread transfer impact

✅ Thread transfer remains within every enforced ceiling.

ℹ️ No successful main baseline artifact is available yet. This run establishes the initial measurement.

Provider	Metric	Main baseline	This PR	Impact	PR ceiling
Codex	Total thread wire	—	4.9 KiB	—	6.8 KiB	✅
Codex	Thread snapshot wire	—	3.8 KiB	—	4.9 KiB	✅
Codex	Live turn WebSocket wire	—	1.2 KiB	—	2.0 KiB	✅
Codex	Live turn WebSocket decoded	—	20.8 KiB	—	29.3 KiB	✅
Codex	Live turn messages	—	1	—	8	✅
Claude	Total thread wire	—	5.0 KiB	—	6.8 KiB	✅
Claude	Thread snapshot wire	—	3.8 KiB	—	4.9 KiB	✅
Claude	Live turn WebSocket wire	—	1.2 KiB	—	2.0 KiB	✅
Claude	Live turn WebSocket decoded	—	21.2 KiB	—	29.3 KiB	✅
Claude	Live turn messages	—	2	—	8	✅

Baseline: unavailable · PR result: 474e92e · Source CI: failure

Scenario and decoded snapshot size

10 historical turns, 5 command tools per turn, 878.9 KiB retained MCP result per historical turn, and a 1.05 MiB retained result in the measured turn.

• Codex decoded thread snapshot: 108.5 KiB
• Claude decoded thread snapshot: 108.8 KiB

Updated in place by a trusted workflow. PR artifacts are strictly validated and never executed.

[juliusmarminge]

Superseded by the squashed 3-PR stack #17299 → #17300 → #17302 (same changes, regrouped; Effect service modules renamed to PascalCase).