perf(db): UNLOGGED permission_reference and LZ4 compression on variable-length columns

Summary

Two PostgreSQL storage optimizations that reduce I/O pressure and improve read latency across dotCMS.

1. Convert `permission_reference` to UNLOGGED

`permission_reference` is a pure denormalized permission cache — rows are rebuilt automatically whenever permissions are invalidated. WAL durability is unnecessary for this table.

Change: `ALTER TABLE permission_reference SET UNLOGGED`

Expected benefits:

• ~2–3× faster INSERT/DELETE throughput during permission rebuilds
• Reduced WAL volume, lowering I/O pressure and replication lag
• Smaller checkpoints during mass permission recalculation

Implementation: `Task260403SetPermissionReferenceUnlogged` — checks `pg_class.relpersistence` to skip if already unlogged; idempotent.

2. LZ4 compression on all text / bytea / jsonb columns

PostgreSQL defaults to pglz for TOAST compression. LZ4 decompresses ~3–5× faster than pglz with comparable compression ratios on typical dotCMS data (HTML, JSON, workflow payloads). Read-heavy workloads (content delivery, page rendering, workflow evaluation) pay the decompression cost on every fetch of a TOASTed column.

Scope: 102 columns across all tables including:

• `contentlet.contentlet_as_json`, `text_area1`–`text_area25`
• `template.body`, `header`, `footer`, `drawed_body`, `head_code`
• `workflow_action.metadata`, `structure.metadata`
• All `bytea` columns (Quartz job data, storage_data)
• `experiment`, `job`, `publishing_queue_audit`, etc.

Notes:

• `SET COMPRESSION lz4` only affects future writes; existing TOAST values rewritten lazily on next UPDATE — migration is instant and lock-free
• Requires PostgreSQL 14+; gracefully skips on older versions
• `postgres.sql` updated with `COMPRESSION lz4` inline in all `CREATE TABLE` column definitions (fresh installs)

Implementation: `Task260403SetLz4CompressionOnTextColumns` — dynamically queries `pg_attribute` to find all eligible columns not yet using LZ4, covers plugin-added columns automatically.

Branch

`feature/postgres-storage-optimizations`

Start with Task260403SetPermissionReferenceUnlogged and Task260403SetLz4CompressionOnTextColumns, then inspect postgres.sql for the corresponding CREATE TABLE definitions. Verify how the migrations detect PostgreSQL capabilities, skip already-compliant columns, and handle plugin-added columns. Done means permission_reference is UNLOGGED and eligible text, bytea, and jsonb columns use LZ4 while older PostgreSQL versions are skipped safely.