docs(readme): correct stale facts after the v0.4.0 refactor

[LukasWodka]

Summary

Three accuracy fixes to the public README, found reviewing it against the shipped v0.4.0. The README's core (the declarative-YAML path, helm flow, metadata-only sync) is current — the refactor was internal and behavior-preserving, so no architecture rewrite is needed. These are stale facts only:

1. Python floor 3.8+ → 3.11+ — the badge and Prerequisites now match setup.py (python_requires=">=3.11", bumped in the P1 packaging phase).
2. Add token_classification to the supported-types table — it's the 11th template (templates/token_classification/) but was missing from the Text/NLP row.
3. Fix the custom-processor example — the old "Subclassing BaseIngestor" snippet showed a validators = [...] class attribute, a transform() hook, and MyIngestor().ingest() that don't exist. Replaced with the real instantiation pattern (CSVIngestor(database=, api_client=, category=, …) + run_ingestion(...)), matching the templates/ scripts and the package's top-level exports.

Type

Docs.

Test plan

Docs-only; no code change. The new example was verified against templates/image_classification/image_classification.py and tracebloc_ingestor/__init__.py exports.

🤖 Generated with Claude Code

[LukasWodka]

👋 Heads-up — Code review queue is at 39 / 30

Above the WIP limit. The team convention is to review existing PRs before opening new work.

Open PRs currently in Code review (oldest first):

• .github#57 — fix(fr-gate): pass items at or beyond the required stage · author: @aptracebloc · no reviewer assigned
• .github#60 — feat(security): public-repo PII gate (block customer names + secrets in PRs) · author: @LukasWodka · no reviewer assigned
• .github#61 — fix(wip-limit): avoid sort|head SIGPIPE failing the WIP check when queue >10 · author: @shujaatTracebloc · reviewer: @saadqbal
• averaging-service#117 — refactor(averaging): per-framework weight-handling seam (WS-B B1) · author: @divyasinghds · no reviewer assigned
• averaging-service#118 — feat(averaging): trainable-only keyed-dict weight format (WS-C image_validator falsely rejects images when target_size matches exactly #104) · author: @divyasinghds · no reviewer assigned
• averaging-service#119 — fix(averaging): exact federated GaussianNB merge — usable + correct (WS-B B2, docs: fix staging-recipe link branch ref (main → develop) #112) · author: @divyasinghds · no reviewer assigned
• backend#815 — chore(deps): bump cryptography from 47.0.0 to 48.0.1 · author: @dependabot · no reviewer assigned
• backend#833 — fix(deploy): graceful shutdown + Dockerfile hygiene; drop dead EC2 script · author: @LukasWodka · no reviewer assigned
• backend#840 — feat(rfc-0001): namespace-slug rule + validation command (#837) · author: @LukasWodka · no reviewer assigned
• backend#843 — fix(test): connect local MySQL test DB over TCP + document mac test-tier setup · author: @LukasWodka · reviewer: @saadqbal

Pull from review before opening new work. (This is a nudge from the kanban WIP check, not a block.)