fix: defer memory file registration until plugins load

[chubes4]

Summary

• Defers default memory file registration until plugins_loaded so Agents API classes are available before MemoryFileRegistry::register() normalizes layers.
• Keeps late bootstrap behavior intact by registering immediately when plugins_loaded has already fired.

Fixes #1993.

Testing

• php -l inc/bootstrap.php
• homeboy test data-machine -- --filter=MemoryPolicyResolverTest

AI assistance

• AI assistance: Yes
• Tool(s): OpenCode (GPT-5.5)
• Used for: Reproducing the bootstrap failure, implementing the boot-order fix, and running focused verification. Chris remains responsible for review and final merge.

[homeboy-ci]

Homeboy Results — data-machine

Lint

✅ lint — passed

ℹ️ Full options: homeboy docs commands/lint
Deep dive: homeboy lint data-machine --changed-since 08a717b

Test

✅ test — passed

• 811 passed
• 3 skipped

ℹ️ Auto-fix lint issues: homeboy refactor data-machine --from lint --write
ℹ️ Collect coverage: homeboy test data-machine --coverage
ℹ️ Save test baseline: homeboy test data-machine --baseline
ℹ️ Pass args to test runner: homeboy test -- [args]
ℹ️ Full options: homeboy docs commands/test
Deep dive: homeboy test data-machine --changed-since 08a717b

Audit

✅ audit — passed

• requested_detectors — 132 finding(s)
• dead_code — 56 finding(s)
• test_coverage — 29 finding(s)
• intra-method-duplication — 9 finding(s)
• parallel-implementation — 7 finding(s)
• dead_guard — 2 finding(s)
• Directives — 1 finding(s)
• Retention — 1 finding(s)
• structural — 1 finding(s)
• Total: 238 finding(s)

Deep dive: homeboy audit data-machine --changed-since 08a717b

Tooling versions

• Homeboy CLI: homeboy 0.174.1+8f66c126
• Extension: wordpress from https://github.com/Extra-Chill/homeboy-extensions
• Extension revision: 03cee04
• Action: unknown@unknown