feat(nebius): sync Token Factory models with automated catalog

[amrrs]

Adds a sync provider for Nebius Token Factory (verbose /v1/models endpoint) so model list, pricing, context length, and capability flags stay in sync automatically, resolving base_model references against canonical models/ metadata where available. Also switches the model sync automation from an hourly to a daily schedule.

[rekram1-node]

Thanks for adding the Nebius Token Factory sync. A few things need addressing before this can go in:

1. Please resolve the merge conflicts

This PR is currently in a conflicting state against dev and can't be merged. Please rebase/merge dev and push.

2. context_length regression — the sync is producing invalid limits

The provider trusts model.context_length as authoritative (const context = model.context_length ?? existing?.limit?.context ?? 0), but the verbose=true endpoint appears to be returning a throttled/default 8000 for a lot of models. That clobbers correct values and yields entries where context < input, which is logically invalid:

model	context (was → now)	input
MiniMax-M2.5	204_800 (canonical) → 8_000	190_000
Qwen3.5-397B-A17B	262_144 → 8_000	250_000
Qwen3-Next-80B-A3B-Thinking	131_072 → 8_000	120_000
Qwen3-32B	131_072 → 40_960	120_000
Llama-3_1-Nemotron-Ultra-253B	128_000 → 8_000	120_000
Nemotron-3-Nano-Omni	65_536 → 8_000	60_000

All of your newly-created models (Kimi-K2.6, Nemotron-3-Ultra, Cosmos3, MiniCPM, etc.) also came through as context = 8_000, which reinforces that the API is handing back a limited value rather than the real context window. This looks like it may be tied to the API key/account tier used to generate the sync — worth double-checking. At minimum the sync should guard against overwriting a larger existing/canonical context with a smaller API value, and never emit context < input.

3. The "hourly → daily" schedule change was documented but not actually made

The PR description and sync.md both say the automation was switched from hourly to daily, but .github/workflows/sync-models.yml still has cron: "17 * * * *" (hourly). So the docs now contradict the workflow. Either make the cron change or revert the sync.md edit. Separately, this is a global change unrelated to adding Nebius — it'd be cleaner as its own PR rather than bundled here.

4. Inconsistent with the other sync providers

Every other provider that resolves canonical base models (baseten, huggingface, vercel, llmgateway) imports the shared resolveCanonicalBaseModel from openrouter.ts. This PR reimplements its own resolveCanonicalBaseModel, modelMetadataExists, and the modelMetadataFilesByProvider cache in nebius.ts. Your NEBIUS_ORG_TO_MODEL_PROVIDER map is essentially a re-keyed subset of openrouter's CANONICAL_PROVIDER_PREFIXES. Consider parameterizing the shared helper with a prefix→namespace map instead of duplicating the file-scan/cache logic, so this stays consistent with the rest of the sync providers.