docs: stale version/flag literals + (TODO) marker shipped in 0.7.0 docs

[avrabe]

Summary

12-persona dogfood pass against rivet 0.7.0 surfaced four stale literals shipped in the embedded docs corpus.

Findings

B1 — Quickstart version oracle stale

rivet docs quickstart Step 1: "Expected: a line of the form rivet 0.5.0 (or higher)." Binary now prints rivet 0.7.0. Oracle still passes ("or higher") but the example is two minor versions stale.

B2 — MCP example hardcodes serverInfo version 0.5.0

rivet docs mcp shows: "serverInfo":{"name":"rmcp","version":"0.5.0"}. Actual on 0.7.0: "version":"1.5.0" (the rmcp crate version, not rivet's).

B3 — Wrong flag in schema/eu-ai-act

rivet docs schema/eu-ai-act shows rivet init --schema eu-ai-act. Real flag is --preset. Copy-paste fails with error: unexpected argument '--schema' found.

B4 — (TODO) marker shipped in schema/dev

rivet docs schema/dev includes literal: "See docs/agent-pipelines.md (TODO) for the full spec". Topic doesn't exist.

Why this is worth fixing

rivet docs check already enforces VersionConsistency on README/CHANGELOG/source files, but does NOT scan the embedded docs strings, NOT catch wrong-flag references, NOT flag (TODO) markers.

Proposed fix

Extend rivet docs check (built on top of the docs-coverage gate from #241) to scan embedded docs for:

1. Version literals — match v?\d+\.\d+\.\d+; assert each matches workspace version or is in explicit allowlist.
2. CLI flag names — every rivet <subcmd> --<flag> in topic bodies must correspond to a real flag in the clap tree.
3. (TODO)/FIXME/XXX markers in shipped docs — fail.

Acceptance

• B1, B2, B3, B4 fixed in their respective doc constants
• rivet docs check extended with the three new invariants
• CI gates new invariants (warn-only first, then strict)

Trigger

Post-0.7.0 12-persona dogfood. Tech writer + DevOps personas independently flagged these.