Update model docs

[l30t]

Updates docs to reflect GLM-4.7 as Droid Core and refreshes multiplier tables to match the current model registry (excluding EAP models). Also adds a note about Claude Opus 4.6 Fast Mode promotional pricing through Monday, February 16.

[factory-droid]

Droid finished @l30t's task —— View job

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• Fetched PR metadata, diff, and changed files
• Checked for existing review threads/comments
• Reviewing for P0/P1 issues introduced by the doc updates

Next: post any required inline comments + submit review summary.

[factory-droid]

Overall these doc updates look correct (GLM-4.6→GLM-4.7 plus a small pricing note). No P0/P1 issues found in the changes.