pipelines: migrate 91 transform_ocsf entries into push/pull/ structure

Moves 91 community pipeline directories from
pipelines/community/transform_ocsf/<name>/ into the ingest-mode-first
taxonomy introduced in #59:

  pipelines/push/syslog/<vendor>/<product>/      57 entries
  pipelines/pull/api/<vendor>/<product>/         29 entries
  pipelines/pull/object_store/<vendor>/<product>/  5 entries

The mode bucket is determined by each entry's ingest_mode field (backfilled
in #61). The vendor and product split is derived per entry from the
upstream parser binding and vendor/product convention; collisions across
the cluster (Cisco Meraki, Fortinet, Cloudflare, Zscaler, Microsoft, etc.)
are disambiguated with explicit product-name overrides documented in
.reorg-prep/inventory/transform_ocsf_migration_plan.tsv.

History is preserved on every entry (git mv).

What stays in pipelines/community/transform_ocsf/ (15 entries):
  - Generic / template / unknown-vendor entries: agent_metrics_logs,
    generic_access_logs, inngate_gateway_logs, json_generic_logs,
    json_nested_kv_logs, leef_template_logs, log4shell_detection_logs,
    mail_server_logs, microservice_tracing_logs, sample_test_logs,
    spam_detection_logs, sql_database_logs, syslog_space_delimited_logs,
    vpc_logs, jruby_application_logs.

What is NOT in this PR (intentional):
  - 23 entries scheduled for removal in #62 (broken-legacy, 7) and #63
    (first-party ingestion paths, 16) are NOT moved; they remain in
    transform_ocsf/ until those PRs merge. This PR has no overlap or
    conflict with #62/#63 -- merge order does not matter.
  - No serializer logic, no metadata.yaml content, and no pipeline JSON
    content was modified. Every change is a directory rename.
  - No naming-consistency cleanup (e.g., paloalto_* -> palo_alto/*) is
    applied yet; that is a separate follow-up.

The pipelines/push/{syslog,hec}/ and pipelines/pull/{api,object_store}/
directories are now populated -- the empty scaffolding from #59 finally
has content.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: Nate Smalley