feat: replace hardcoded Uniswap API key with per-operator developer-portal key

[Ponx]

Why

The Uniswap plugin shipped a shared, hardcoded x-api-key in ## Auth. This is counter to Uniswap's legal posture and operationally fragile:

• A public key lets anyone call the API without being bound to Uniswap's developer terms (they never accept anything).
• All usage pools onto one key's RPS budget, so any single user can starve the rest.
• A public key predictably accumulates spam traffic.

The fix is to have each operator generate their own free key on the Uniswap developer portal, which binds their usage to the terms and scopes rate limits to them.

What changed

skills/base-mcp/plugins/uniswap.md:

• Removed the hardcoded key; the header block now uses a <UNISWAP_API_KEY> placeholder (also required by the plugin spec — no secret values in plugin files).
• Rewrote ## Auth:
  • "Obtaining a key" flow → sign up at https://developers.uniswap.org/dashboard/welcome (Google/GitHub/email); account creation auto-generates a key.
  • Two completion paths: operator-driven (default — prompt the human for their key) and agent-driven (only when the harness controls both a browser and an inbox, it may register itself and read the key from the dashboard).
  • Key-handling rules: prefer a harness secret/env var, paste the key in full, never echo/log it or place it in send_calls calldata, one key per operator.
• Added a second > [!IMPORTANT] onboarding callout flagging the key as a prerequisite, plus a Notes pointer to the portal.
• Bumped version 0.2.0 → 0.3.0.

skills/base-mcp/SKILL.md:

• Updated the Uniswap catalog row to note the free developer-portal API-key requirement. (Maintainer-managed file — included for catalog accuracy; happy to drop if reviewers prefer the diff scoped to the plugin file.)

Notes for reviewers

• Header name (x-api-key) and the auto-generation-on-signup flow were confirmed against Uniswap's Trading API quickstart / overview. The exact post-signup dashboard UI is behind auth and was not directly verified.

🤖 Generated with Claude Code

[cb-heimdall]

🟡 Heimdall Review Status

Requirement	Status	More Info
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