Add a 'Putting it together' section to the README — document how the skills compose into a lifecycle

[erikpr1994]

The README does a great job explaining why each skill exists (the four failure modes) and listing them in the reference. What it doesn't document is how the skills compose into a sequence — the lifecycle is only implied by the failure-mode narrative. There's no explicit flow, no diagram, and no skill names its upstream/downstream neighbors, so composing two skills means inferring the seam between them. (This is really the root of #287 — the improve-codebase-architecture → to-issues handoff is unclear because the composition isn't documented anywhere.)

Proposal: a short "Putting it together" section in the README (a section, not a separate file — discoverability) that lays out the intended flow, e.g.

grill-with-docs / grill-me  →  to-prd  →  to-issues  →  tdd
improve-codebase-architecture · triage · diagnose   (ongoing)

…with one line per hop on what each step consumes and produces (e.g. "to-issues: takes an approved plan/PRD → emits independently-grabbable vertical-slice issues").

Two open questions for you:

1. Is there a single canonical sequence you intend, or is it deliberately more of a toolbox where steps are mixed as needed?
2. Where do the "ongoing maintenance" skills (improve-codebase-architecture, triage, diagnose) sit relative to the change flow?

Happy to open a PR drafting the section once you confirm the intended sequence — I didn't want to codify a flow you didn't intend.