feat(sdk): improve read_url error diagnostics and html table extraction

[nilaymallikk]

Summary

Closes #1121.

Enhances the read_url tool in @codebuff/sdk and common tool schemas:

• Structured Error Diagnostics: Adds typed error classifications (errorCode such as HTTP_ERROR, BLOCKED_ADDRESS, INVALID_URL, TOO_MANY_REDIRECTS, UNSUPPORTED_CONTENT_TYPE, RESPONSE_TOO_LARGE, TIMEOUT, ABORTED) and forwards HTTP status codes (e.g. 404, 429, 500) so caller agents can differentiate retryable rate-limits from permanent errors.
• HTML Table Extraction: Added formatHtmlTables pre-processor during HTML readable text extraction to transform <table> elements into structured GitHub-Flavored Markdown tables instead of flattening cells into unformatted lines.

Scope

All changes are strictly scoped within:

• sdk/src/tools/read-url.ts
• sdk/src/__tests__/read-url.test.ts
• common/src/tools/params/tool/read-url.ts

Verification

• Passed unit tests: bun test sdk/src/__tests__/read-url.test.ts (21 pass)
• Passed full SDK test suite: bun test sdk/src/__tests__/ (470 pass)
• Passed CI build and packaging: bun run ci
• Passed binary smoke test: bun cli/scripts/smoke-binary.ts cli/bin/freebuff