e32: Missing Historical References — 9 new reference docs

[danielvm-git]

Epic e32: Missing Historical References

WSJF: 3.0 · BCP: 20 · Stories: 10
Source: specs/MISSING-REFERENCES-AND-DELIVERY-PLAN.md §1 + §4 Epic 3

Add the 9 missing historical reference docs to docs/references/ and cross-reference them from skills that use their concepts.

Stories

#	BCP	Title
e32s01	2	Create docs/references/kent-beck.md (XP, TDD origins, Tidy First? tidy vs refactor vs behavior)
e32s02	2	Create docs/references/fowler.md (refactoring catalog, code smells, named refactorings)
e32s03	2	Create docs/references/feathers.md (seams, characterization tests, legacy code definition)
e32s04	2	Create docs/references/pragmatic-programmer.md (DRY, broken windows, tracer bullets)
e32s05	2	Create docs/references/rich-hickey.md (simple vs easy, complecting)
e32s06	2	Create docs/references/sandi-metz.md (SOLID in practice, message-level testing)
e32s07	2	Create docs/references/ddd.md (bounded contexts, context mapping, ubiquitous language)
e32s08	2	Create docs/references/accelerate.md (DORA four keys: deployment frequency, lead time, restore time, change failure rate)
e32s09	2	Update PRINCIPLES.md to credit Beck, Fowler, Feathers, Hunt & Thomas alongside Uncle Bob in layer 1
e32s10	2	Cross-reference new docs from SKILL.md bodies (plan-refactor → fowler, audit-code → fowler smells, investigate-bug → feathers, grill-me → hickey)

What Each Doc Contains

Each reference doc is a provenance pointer — not a restatement of principles. ~10 lines: source, key contributions, why it matters for bigpowers, and where the rules are encoded in CONVENTIONS.md.

Definition of Done

• 9 new docs in docs/references/
• PRINCIPLES.md updated to credit all 9 authors
• At least 4 skills cross-reference the new docs