Add user-friendly error messages for API failures

[robertmclaws]

Summary

• The plugin previously swallowed all API errors silently via .catch(() => null) in context-hook.js, making 400/401/403/429 errors indistinguishable from "No previous memories found". Users had zero indication when their API key was invalid, expired, or rate-limited.
• Added a shared error utility (src/lib/error-helpers.js) that maps SDK error status codes to actionable, user-facing messages with links to relevant console/pricing pages.
• Replaced the silent .catch(() => null) in context-hook.js with error-aware handlers that distinguish benign errors (404, network blips) from real problems (400, 401, 403, 429, 5xx) and surface the latter via <supermemory-status> tags.
• Updated catch blocks in summary-hook.js, add-memory.js, search-memory.js, and save-project-memory.js to use the new getUserFriendlyError() helper.

Relates to #26

Files changed

File	Change
src/lib/error-helpers.js	New — getUserFriendlyError(), isRetryableError(), isBenignError()
src/context-hook.js	Replace .catch(() => null) with error-aware handlers; surface API errors
src/summary-hook.js	Use getUserFriendlyError() in catch block
src/add-memory.js	Use getUserFriendlyError() in catch block
src/search-memory.js	Use getUserFriendlyError() in catch block
src/save-project-memory.js	Use getUserFriendlyError() in catch block

Design decisions

• Uses err.status property checks rather than instanceof SDK error classes to avoid bundling/import-path issues
• Benign errors (404 = no data yet, connection errors = transient) still return null silently, matching the previous graceful behavior
• Non-benign errors are collected and deduplicated, then prepended to the context output as a <supermemory-status> block
• The plugin never crashes on errors — all paths still produce valid output

Test plan

• Verify normal flow (valid API key, memories exist) still works unchanged
• Simulate a 400 error and confirm the user sees the "Bad request" message with console link
• Simulate a 401 error and confirm the authentication-failed message appears
• Simulate a 429 error and confirm the rate-limit message appears
• Verify 404 errors (no data yet) still show "No previous memories found" without error noise
• Verify network/connection errors are treated as benign (no scary error messages)

🤖 Generated with Claude Code

[robertmclaws]

Just an FYI, this came about because the plugin installation process used Powershell to add the Supermemory key, which only kept it in the Environment variables for the session. When the session restarted, the key was gone, and subagents started throwing 400 errors without source information that had to be tracked down.

This PR attempts to solve that problem by handling the API exceptions and turning them into user-actionable error messages so they don't have to waste tokens solving the problem.