Remove stale monorepo artifacts

[bpamiri]

Summary

• Remove templates/ directory (contained only an outdated CLAUDE.md no longer referenced by build scripts)
• Remove .github/workflows/tests.yml.keep (legacy workflow with old path references)

Closes #1956

Test plan

• No build scripts reference templates/ — verified by repo search
• CI passes without the removed files

🤖 Generated with Claude Code

[github-actions]

Wheels Test Matrix

Engine	MySQL	PostgreSQL	SQL Server	H2	Oracle	SQLite
lucee5	✅	✅	✅	✅	✅	✅
lucee6	✅	✅	✅	✅	✅	✅
lucee7	✅	✅	✅	✅	✅	✅
adobe2018	✅	✅	✅	--	✅	--
adobe2021	✅	✅	✅	--	✅	✅
adobe2023	✅	✅	✅	--	✅	✅
adobe2025	✅	✅	✅	--	✅	✅
boxlang	✅	✅	✅	--	✅	✅

Results for commit 7686566.

[github-actions]

Wheels Test Results

    42 files  ±0   3 906 suites  ±0   25m 16s ⏱️ -20s
79 512 tests ±0  79 124 ✅ ±0  388 💤 ±0  0 ❌ ±0 
82 158 runs  ±0  81 770 ✅ ±0  388 💤 ±0  0 ❌ ±0 

Results for commit 82ab9d2. ± Comparison against base commit e57ecf8.