fix(cli): configure Vercel AI SDK instrumentation in Auto tracing setup

[Nightingalelyy]

Problem

respan setup tracing delegates project changes to the bundled Respan skill. Its Auto path previously prohibited every framework instrumentor. Because Vercel AI SDK instrumentation is intentionally explicit-only, a core-only new Respan() setup left direct ai calls uninstrumented.

Fix

• Detect direct Vercel AI SDK usage and configure @respan/instrumentation-vercel.
• Install @ai-sdk/otel for AI SDK 7 and enable the version-appropriate per-operation telemetry option.
• Preserve existing Respan instances, user-owned telemetry registration, Next.js server placement, and higher-level ownership precedence such as Eve.
• Regenerate the CLI-embedded skill, synchronize the Claude/Cursor mirrors, and add an Auto-path regression test.

Vercel remains disabled in runtime auto-discovery by design: its framework-level spans can overlap provider instrumentation. The CLI now adds it explicitly for direct ai usage without broadening facade auto-discovery or introducing duplicate spans.

Regenerating the mirrors also reconciles their pre-existing drift from the canonical direct-LLM support table.

Verification

• cd javascript-sdks/respan-cli && npm test — 2/2 passed
• cd javascript-sdks/instrumentations/respan-instrumentation-vercel && npm test — 47/47 passed
• python3 scripts/release_inventory.py --validate — passed
• python3 scripts/release_intents.py validate — passed
• Local npm pack smoke — extracted package contains the complete Vercel Auto setup
• Bundle/source and Claude/Cursor mirrors match
• No-network AI SDK 7.0.58 + @ai-sdk/otel 1.0.0 generateText smoke — exported the canonical agent → task → LLM hierarchy with prompt, completion, provider, model, and token fields; no raw ai.* fields remained
• git diff --check — passed

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[Nightingalelyy]

Related work

PR #396 changes the same Auto-mode provider-list sentence and generated skill copies. This PR intentionally preserves Vercel as an explicit-only Auto exception, while #396 corrects the per-language direct-provider list. Whichever PR merges second should rebase, regenerate all skill copies, and retain both changes so neither wording overwrites the other.