v0.37.1 — make every skill installable, and add the one that routes to the rest

Makes every skill in this repo actually installable, and adds the entry-point
skill that says which of the twenty tools answers a given question.

• feat(skills) — all thirteen skills are registered. Nine of them
  (crypto-data, surf, rpc, search, image-prompting, phone, modal,
  gentech-blockrun and the new core skill) sat on disk while
  .claude-plugin/marketplace.json listed only four, so /plugin marketplace add could not reach them. No decision was ever taken to withhold them:
  entries had been added alongside the skill that prompted them, and the rest
  were never backfilled. Now 13 on disk, 13 registered, no orphans.

  Verified by installing rather than by reading the JSON — claude plugin marketplace add against the checkout, then install plus plugin details
  on blockrun, search, rpc, signal-to-trade-demo and
  gentech-blockrun. Each reports Skills (1). That also settles a standing
  question about the layout: a plugin directory with SKILL.md at its root and
  no .claude-plugin/plugin.json does register its skill, which is what every
  entry here has always relied on.

• feat(skills) — new skills/blockrun core skill. The entry point the
  repo lacked: tool routing, how the wallet works, and how to get a first call
  working for free. Wallet, budget and x402 mechanics live in
  rules/wallet-and-payment.md so SKILL.md stays small enough to load on
  every match — measured at ~405 always-on tokens against ~3.1k on invoke.

  It deliberately carries no price table, and says why: every flat per-call
  price published in this repo's other skills is one retired $0.002
  transaction fee too high, because each was a typed copy. It points at
  blockrun_models, the 402 itself and llms.txt instead.

• fix(skills) — seven claims in the new skill corrected against src/.
  Found by reviewing it against the code rather than the marketing copy. The
  worst two were the same failure the skill itself warns about:

  routing: "free" is not a parameter — blockrun_chat takes mode. Because
  the tool declares a raw zod shape, the SDK strips the unknown key rather than
  erroring, mode falls through to "balanced", and the paragraph headed
  "Free, no wallet, no key" made a paid frontier call. And "six open-weight
  chat models" is eight; that count and the RPC chain count are now
  br: markers fed by brand-numbers.json and enforced by
  sync-brand-numbers --check in CI, because an unmarked number is invisible
  to that check — which is precisely how the prices drifted.

  Also: blockrun_polymarket_read was missing entirely, so "what are my
  positions?" routed to the money-moving tool rather than the free read-only
  one; blockrun_realface was listed in the frontmatter but had no row, so it
  was advertised and unroutable; action:"deposit" is the Coinbase card onramp
  (launchTopUp, Base only), not "deposit details", which is why the funding
  steps hand-rolled POST /api/v1/onramp/token instead of calling the tool
  that does it; api_key="not-needed-for-free-models" appears nowhere in this
  repo or in either SDK and was dropped; and the free tier does not truncate
  silently — freeTierTruncationNote() reports the dropped fraction through
  the MCP, so only the direct HTTP path is silent.

  Tool coverage is now 20/20 against the names registered in src/, in both
  the frontmatter and the routing table, with no orphans in either direction.

Known and not fixed here, each wanting its own pass: the flat prices in the
other eleven skills are still a fee high, and skills/prediction-markets still
advertises dFlow, whose three paths have returned upstream 404 since
2026-08-04. A partial sweep would leave those files half-right, which is the
failure mode that produced the drift in the first place.