feat: consolidate 25 historical 2.x migrations into single end-of-2.7 schema

Generated via `doctrine:migrations:diff --formatted` against an empty
test DB with the 3.0 entity metadata (which now carries icon, resources,
and description as deprecated properties matching 2.7). The diff command
is used because dump-schema in doctrine/migrations 3.7 silently omits
foreign key constraints; diff produces the full schema including all
96 FK clauses.

The 3.0-only `Version20250815092648` (template column drop) is removed
here as well — it's deferred to 3.1 along with the entity properties so
fresh and upgraded 3.0 installs stay schema-symmetric.

Verified end-to-end:
- Fresh install: drop DB → migrate → schema:validate exits 0
- Upgrade from 2.7: 25 latest-2.x applied → swap files → rollup → status
  shows 1 executed / 1 available / 0 unavailable; schema:validate exits 0
- Full PHPUnit suite: 143 tests / 607 assertions green

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

Author: turegjorup