Expose documents to agents without growing the MCP tool surface #273

Work

• Reading, history, archiving and deletion: extend item_get, item_history, item_archive and item_delete to the page kind. No new read tool.
• Writing: reuse the store and proposal path; justify any new tool explicitly against the tool budget from #256 (McpDiscoveryTests.ToolListStaysWithinItsContextBudget).
• Recall lists relevant pages by number and title within its budget, never their content.
• Search covers page titles and bodies with an explicit scope. This is the place to introduce item_search, which #256 deliberately left out because tasks are not searchable yet.
• Update system_memory, server instructions and examples so agents know when to write a page instead of a memory.

Acceptance

• The budget test passes; any increase is a recorded decision.
• A fresh agent finds and reads the security review from a #N reference alone.
• Recall stays within budget with a large page tree.