Clarify reader/writer role descriptions in docs

[devin-ai-integration]

Summary

Updates the role capabilities table in both usage/rbac.mdx and usage/teams.mdx to clarify that Reader/Writer roles only govern permissions for the shared context index (indexed repositories), not plans. Previously the descriptions used vague terms like "Search resources" and "Search only" which could imply these roles restrict plan access too.

Changes in both files:

• "Search resources" → "Search context index"
• "add content" → "add content to index"
• "Search only" → "Search context index"
• Added a blockquote note clarifying that all team members can read and write plans regardless of role

Review & Testing Checklist for Human

• Verify the updated capability descriptions accurately reflect actual product behavior (e.g., Readers really can only search the context index, Writers really can add to it)
• Confirm that the added note is factually correct — all roles can indeed read and write plans with no restrictions
• Check that the rendered markdown tables and blockquote look correct on the docs site (preview deploy or local build)

Notes

• Both files received identical table and note changes to keep them consistent

Link to Devin session: https://app.devin.ai/sessions/d2bf042cee674113894b721fcd296ff9
Requested by: @MatthewDailey

[devin-ai-integration]

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