Enforce annotations for readOnlyHint and destructiveHint

[geoffg-sentry]

Fixes #1143. Every catalog tool now declares complete MCP safety annotations, and this is enforced so gaps can't be reintroduced.

• Require complete hints at the type level: readOnlyHint, destructiveHint, and openWorldHint are now required on ToolConfig.annotations (each must be an explicit true/false). A missing hint is now a tsc error.
• Backfill read-only tools: added the previously-omitted destructiveHint: false to every read-only tool (all find_*/get_*/search_*/whoami, plus search_sentry_tools). The write tools already declared both hints on main; the gaps listed against 3705c15 were already fixed.
• Strengthen the deterministic test: tools.test.ts now asserts all three hints are explicit booleans on every registered tool (not just when readOnlyHint === false) and that no tool is both read-only and destructive.
• Docs: updated docs/contributing/adding-tools.md, whose examples were teaching the incomplete pattern, to reflect the requirement.

Will follow up afterwards to deprecate use_sentry since tool catalogs are our preferred way now.

[dcramer]

so my only concern is the change to use_sentry

thats agent mode and it wraps all tools - of which users explicitly select what tools they want. so us not allowing write tools there would actually be counter to the intent users select

i think we should just make use_sentry always dangerous? to be fair, agent mode probably is gonna die as well. so we could consider just removing it at this point instead

[geoffg-sentry]

Yeah that makes sense, good justification on why we'd want move in that direction too. I'm going to drop user_sentry from /chat keepAnyway so the demo is fully read-only instead,

[geoffg-sentry]

And reverted that use_sentry change because we're just going to deprecate it afterward