fix: purge dm_ prefix remnants in favor of datamachine_

[chubes4]

Summary

• Purges live dm_ prefix remnants in favor of datamachine_.
• Adds WebhookTrigger::rate_limit_transient_key() so webhook rate-limit read/delete paths share one key builder.
• Updates tests and test fixtures/helpers so the active code/test audit paths are clean.

Rename inventory and persistence assessment

• dm_backpressure_ -> datamachine_backpressure_ in RunFlowAbility crc32 jitter seed. Persistence: none; this only shifts deterministic defer jitter.
• dm_email_sent_folder_from -> datamachine_email_sent_folder_from in EmailAbilities. Persistence: none, but this is a public filter hook rename and is a breaking change for consumers of the old filter.
• dm_img_ -> datamachine_img_ in GDRenderer tempnam prefix. Persistence: none; temporary filename prefix only.
• dm_webhook_rate_ -> datamachine_webhook_rate_ in webhook rate-limit transients. Persistence: short-lived transient state; old transient keys are intentionally not migrated and will expire. Read/delete paths now share WebhookTrigger::rate_limit_transient_key() to keep them in sync.
• dm_batch_ -> datamachine_batch_ for TaskScheduler batch IDs. Persistence: batch IDs are stored in job engine data/log context as opaque identifiers. Repo audit found no prefix parsing/matching/read branches for dm_batch_, so new writes hard-cut to datamachine_batch_ without dual-prefix read compatibility. Existing in-flight old IDs remain opaque values on already-created batch parent jobs.
• dm_stagger_ -> datamachine_stagger_ in RecurringScheduler crc32 stagger seed. Persistence: none; this only shifts deterministic stagger offsets.
• $dm_version -> $datamachine_version in migration scaffolding. Persistence: none; local variable only.
• Test-only helper/function/global/fixture remnants (dm_assert, dm_test_*, dm_rs_*, dm_hook, dm_cron, dm_once, dm_dup, dm_name, dm_wp_error_terms, etc.) were renamed to datamachine_ equivalents so the active test paths are clean too.

Breaking changes

• Public filter hook dm_email_sent_folder_from is now datamachine_email_sent_folder_from. No backwards-compat shim is included by design.

Audit evidence

• git grep -n "dm_" -- inc tests data-machine.php uninstall.php returned no matches.
• git grep -n "'dm_\|"dm_" -- inc tests data-machine.php uninstall.php returned no matches.
• git diff --check passed.

Test evidence

• php -l passed for every changed PHP file.
• composer test did not reach the test suite: Homeboy offloaded to homeboy-lab and failed preflight because runner extension parity for wordpress is stale and cannot auto-sync from controller-local source /Users/chubes/.config/homeboy/extension-sources/wordpress/wordpress.
• Attempted the intended repair path, homeboy extension dev-run --source /Users/chubes/.config/homeboy/extension-sources/wordpress/wordpress --runner homeboy-lab wordpress homeboy test data-machine; it also failed before tests because the runner-side command could not resolve server homeboy-lab (server.not_found).

AI assistance

• AI assistance: Yes
• Tool(s): opencode — Claude Fable 5 (Anthropic) orchestrator, GPT 5.5 (OpenAI) implementation subagent
• Used for: Audited prefix usage, implemented the hard-cut renames, updated tests, and prepared verification/PR notes.

[homeboy-ci]

Homeboy Results — data-machine

Lint

✅ lint — passed

ℹ️ Full options: homeboy docs commands/lint
Deep dive: homeboy lint data-machine --changed-since 28dd1a0

Artifacts and drill-down

• CI results artifact: homeboy-ci-results-data-machine-lint-quality-Linux-node24 contains immediate command JSON for this action invocation.
• Observation artifact: homeboy-observations-data-machine-lint-quality-Linux-node24 contains exported Homeboy run history for deeper queries.
• Drill-down: download the observation artifact, then run homeboy runs import <dir>, homeboy runs list, and homeboy runs findings <run-id>.
• Artifacts are attached to the workflow run: https://github.com/Extra-Chill/data-machine/actions/runs/28680895064

Test

❌ test — failed

ℹ️ No tests ran — the runner failed before producing results. See raw_output.stderr_tail / raw_output.stdout_tail for the underlying error (bootstrap failure, missing deps, DB connection, etc.).
ℹ️ To run specific tests: homeboy test data-machine -- --filter=TestName
ℹ️ Auto-fix lint issues: homeboy refactor data-machine --from lint --write
ℹ️ Collect coverage: homeboy test data-machine --coverage
ℹ️ Analyze failures: homeboy test data-machine --analyze
ℹ️ Pass args to test runner: homeboy test -- [args]
ℹ️ Full options: homeboy docs commands/test
Deep dive: homeboy test data-machine --changed-since 28dd1a0

Artifacts and drill-down

• CI results artifact: homeboy-ci-results-data-machine-test-quality-Linux-node24 contains immediate command JSON for this action invocation.
• Observation artifact: homeboy-observations-data-machine-test-quality-Linux-node24 contains exported Homeboy run history for deeper queries.
• Drill-down: download the observation artifact, then run homeboy runs import <dir>, homeboy runs list, and homeboy runs findings <run-id>.
• Artifacts are attached to the workflow run: https://github.com/Extra-Chill/data-machine/actions/runs/28680895064

Audit

✅ audit — passed

• audit — 533 finding(s)
• Total: 533 finding(s)

Deep dive: homeboy audit data-machine --changed-since 28dd1a0

Artifacts and drill-down

• CI results artifact: homeboy-ci-results-data-machine-audit-quality-Linux-node24 contains immediate command JSON for this action invocation.
• Observation artifact: homeboy-observations-data-machine-audit-quality-Linux-node24 contains exported Homeboy run history for deeper queries.
• Drill-down: download the observation artifact, then run homeboy runs import <dir>, homeboy runs list, and homeboy runs findings <run-id>.
• Artifacts are attached to the workflow run: https://github.com/Extra-Chill/data-machine/actions/runs/28680895064

Tooling versions

• Homeboy CLI: homeboy 0.280.13+89fee93c89fb+9205bd15
• Extension: wordpress from https://github.com/Extra-Chill/homeboy-extensions
• Extension revision: ec4685ca
• Action: unknown@unknown