feat(pgpm/core): add smart error output collapsing and limiting

[pyramation]

Summary

Reduces verbosity of error output when migrations fail with many pgpm_migrate.deploy calls. Previously, a failed deployment with 1600+ migrations would output 1600+ lines of query history. Now, consecutive identical queries are collapsed into a summary showing the range, count, and first/last change names.

Key changes:

• Smart collapsing of consecutive identical queries (e.g., "2-57. CALL pgpm_migrate.deploy... (56 calls)")
• For deploy calls, shows first and last change names for context
• Configurable via environment variables:
  • PGPM_ERROR_QUERY_HISTORY_LIMIT (default: 30 queries)
  • PGPM_ERROR_MAX_LENGTH (default: 10000 chars)
  • PGPM_ERROR_VERBOSE=true to disable all limiting
• Added comprehensive test suite (11 tests including snapshot test for exact output format)
• Updated README with configuration documentation
• Environment variables follow centralized pattern via @pgpmjs/env and @pgpmjs/types

Review & Testing Checklist for Human

• Test with a real failed deployment - Trigger a migration failure with many deploy calls and verify the output is readable and still contains useful debugging info
• Verify env vars work - Test that PGPM_ERROR_VERBOSE=true shows full output, and that the limit vars work as expected
• Check edge cases - What happens when the error occurs on the first query? When there's only one query? When all queries are different?
• Verify code organization - Confirm the new errors.ts file is properly separated from transaction.ts and imports work correctly

Recommended test plan:

1. Run the new tests: cd pgpm/core && pnpm test -- error-output-formatting
2. Manually trigger a deployment failure with many migrations and verify the collapsed output
3. Set PGPM_ERROR_VERBOSE=true and verify full output is shown

Notes

• The collapsing is generic (works for any repetitive query pattern), but has special handling for pgpm_migrate.deploy to extract change names from params
• Environment variables are read at module load time via getErrorOutputConfig(), so changes require process restart
• The extractDeployChangeName function assumes params[1] is the change name - this matches the current pgpm_migrate.deploy signature

Updates since last revision

• Fixed test assertions to match actual output format (collapsed groups include First/Last context lines)
• Added additional integration test for truncation behavior when exceeding query limit
• Refactored to use centralized env var parsing: added ErrorOutputOptions interface to @pgpmjs/types, added errorOutput to PgpmOptions and pgpmDefaults, added env var parsing in @pgpmjs/env, updated transaction.ts to use getErrorOutputConfig() instead of direct process.env access
• Fixed snapshot test in pgpm/env to include the new errorOutput field in getEnvVars() return value
• Code organization refactor: Extracted all error formatting logic (~200 lines) into new errors.ts file, keeping transaction.ts focused on transaction lifecycle. Functions are re-exported from transaction.ts for backward compatibility.
• Added snapshot test: New snapshot test captures the exact error output format for a realistic deployment scenario, serving as documentation and regression protection

Link to Devin run: https://app.devin.ai/sessions/c634626524714b3596c4d506d7f94a9a
Requested by: Dan Lynch (@pyramation)

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