feat(mcp): expose MCP resources and prompts, not just tools

[BryanFRD]

Problem

The six servers expose tools and nothing else. There is no server.resource(...) or server.prompt(...) call anywhere in packages/.

Why it matters

Everything a client wants as ambient context has to be fetched by an explicit tool call that spends a turn and lands as a blob in the transcript. Resources exist for exactly that: the client attaches them, the user sees what is attached, and the content does not have to be re-fetched per question.

Natural fits already backed by existing handlers:

• ferrlabs://org/{slug}/overview — get_org_overview, packages/mcp/src/tools/org-admin.ts:107
• ferrlabs://org/{slug}/usage — get_org_usage, org-admin.ts:120
• ferrtrack://project/{slug}/issues — packages/mcp-track/src/tools/issues.ts
• ferrvault://vault/{id} (metadata only, never values) — packages/mcp-vault/src/tools/vault-details.ts

Prompts are the other half — the repeated workflows a user drives by hand today: triage a FerrTrack backlog, review an org's vault audit log, summarise a FerrFleet run.

Proposed approach

• Add read-only resources for the org/project/site overviews, reusing the existing fetch functions rather than duplicating them.
• Add a small set of prompts, starting with FerrTrack triage and FerrFleet run review.
• Declare the resources and prompts capabilities in the server construction so clients discover them.
• Vault resources expose metadata only — secret values stay behind get_secret and its reveal gate.

Acceptance criteria

• resources/list and prompts/list return a non-empty set on the relevant servers.
• Resource handlers share the tool fetch path (no second copy of the URL building).
• The README documents which resources and prompts each server exposes.