feat: auto-discover per-view JSON schemas by convention

[flyingrobots]

Context

The view progress --json output is validated against view-progress.schema.json (added in #222). Currently the schema filename is hardcoded in the contracts table and test samples. As more views gain --json support, each will need a manual schema entry.

Proposal

Auto-discover per-view schema files by convention: view-{name}.schema.json in docs/contracts/cli/. When view <name> --json is invoked, the CLI (or test harness) could resolve the schema file automatically:

const schemaFile = `view-${viewName}.schema.json`;

This would apply to:

• Contract test discovery (contracts.test.js — scan for view-*.schema.json)
• Integration canary generation (one canary per discovered view schema)
• CLI outputJson routing (optional — could validate output before emitting)

Acceptance Criteria

• contracts.test.js auto-discovers view-*.schema.json files
• Adding a new view schema doesn't require updating VALID_SAMPLES manually (or at least fails clearly)
• Existing views without schemas are unaffected

Originated from PR #223 agent reflection.