docs: add GPT-5.3-Codex and MiniMax M2.5 to model documentation

[factory-sagar]

Summary

Add two newly released models to all documentation tiers:

New Models

Model	Model ID	Multiplier	Reasoning	Default
GPT-5.3-Codex	gpt-5.3-codex	0.7×	None/Low/Medium/High/Extra High	Medium
Droid Core (MiniMax M2.5)	minimax-m2.5	0.12×	Low/Medium/High	High

Files Updated

Tier 1 (model tables):

• docs/pricing.mdx — pricing table
• docs/reference/cli-reference.mdx — available models table
• docs/cli/user-guides/choosing-your-model.mdx — stack rank, job matching, reasoning settings, open-source section, date

Tier 2 (model lists):

• docs/cli/configuration/settings.mdx — model options and descriptions
• docs/cli/droid-exec/overview.mdx — supported models list

Tier 3 (references):

• docs/guides/power-user/token-efficiency.mdx — cost multipliers table

Verification

• All ranks sequential (1-16), no gaps or duplicates
• Cross-file consistency confirmed (names, IDs, multipliers match everywhere)
• No changelog files modified
• Local mintlify dev build renders all pages correctly

[factory-droid]

Overall the documentation updates look consistent and correct for adding gpt-5.3-codex and minimax-m2.5. No P0/P1 issues found in the current diff; nothing blocking.