fix(mcp-config-validator): remove invented trust field (verify-first)

`.mcp.json` has no per-server `trust` key — verified 2026-06-18 against
code.claude.com/docs/en/mcp + /settings. MCP server approval is
dialog/settings-based (enableAllProjectMcpServers / enabledMcpjsonServers /
disabledMcpjsonServers), never a JSON field. The scanner's "Missing trust
level" (CA-MCP-001, medium) and "Invalid trust level" (high) were false
positives flagging a field that does not exist.

- scanner: delete both trust checks + VALID_TRUST_LEVELS; drop `trust` from
  VALID_SERVER_FIELDS so a stray `trust` is now flagged as an unknown field
- humanizer: remove the two trust-level entries
- knowledge (5 files): point to the real approval mechanism, not a trust field
- fixtures: scrub `trust` (incl. the invalid "local" in optimal-setup)
- tests: flip assertions (no trust-level finding; stray trust -> unknown
  field) + add knowledge-staleness re-freeze guards
- snapshots: reseed (marketplace-medium .mcp.json -8 tokens, hermetic)
- gap-matrix: mark the trust verify-first item DONE

Suite: 853/853 green.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Ter3E2JSi1Khgmuf2kady8

scanners/lib/humanizer-data.mjs

@@ -273,16 +273,6 @@ export const TRANSLATIONS = {
         description: 'The `type` field doesn\'t match one Claude Code knows how to start (typically `stdio`, `sse`, or `http`).',
         recommendation: 'Change the `type` to one of the supported values shown in the details.',
       },
-      'Invalid trust level': {
-        title: 'A connected service has an unrecognized trust setting',
-        description: 'Trust controls whether Claude can use the service\'s tools without asking.',
-        recommendation: 'Set the trust value to one of the accepted ones (see details).',
-      },
-      'Missing trust level': {
-        title: 'A connected service has no trust setting',
-        description: 'Without an explicit trust value, Claude has to ask before each tool use, which slows your work.',
-        recommendation: 'Add a trust value to the entry. The details show the accepted values.',
-      },
       'Unknown MCP server field': {
         title: 'A connected service has an unrecognized setting',
         description: 'The setting isn\'t one Claude Code reads, so it will be ignored.',