docs(init): validate specification — v1.23 milestone (REQ-263..275)

Established active_milestone: v1.23 (Nova Deck Cleanup & Python PPTX).
NFR milestone (docs/render/test only; no features). Tags on v1.22.x line
(v1.22.0 P0 -> v1.22.6 P6 final = milestone release). Branch:
milestone/v1.23-deck-cleanup-python-pptx.

Added REQ-263..275 to REQUIREMENTS.md covering:
- Consolidate docs: single -marp.md source of truth, delete plain .md,
  speaker notes/talking points as Marp HTML comments, keep
  talking-points.md as synced standalone aid (REQ-263,264)
- Restore clean style: theme:default + inline style block (S&P palette),
  retire nova-sp-theme.css from render (keep as reference), benefit
  callout restyle (REQ-265,266,267)
- Inline images: scripts/inline_images.py for self-contained
  redistributable HTML (REQ-268)
- Python PPTX generator: scripts/render_pptx.py structured editable
  S&P-themed PPTX via python-pptx, both PPTX outputs produced + attached
  (REQ-269,270)
- Trim word count: targeted ~20-30% trim on verbose slides, remove
  'penetrate' term (REQ-271,272)
- CI/tests/README: workflows install python-pptx, tests updated,
  README rewritten (REQ-273,274,275)

Driven by user feedback: deck looked 'out of whack'; wanted to return to
the clean style of the old the-developer-experience.html. Investigation
revealed the 'clean' reference was itself MARP output (default theme +
inline style); the standalone nova-sp-theme.css approach was fragile.

---ci---
project: acdl
phase: 0
milestone: v1.23
status: specify
---/ci---

.ciagent/PROJECT.md

@@ -1532,3 +1532,48 @@ New requirements REQ-254..REQ-262 — see `REQUIREMENTS.md` §v1.22. Summary:
   A1) + remove redundant `header:` from frontmatter.
 - **REQ-262:** Re-render HTML + PPTX + add layout/aspect-ratio/theme-
   structural tests.
+
+## v1.23 — Nova Deck Cleanup & Python PPTX
+
+> **Active milestone.** NFR (docs/render/test only; no features).
+> Branch: `milestone/v1.23-deck-cleanup-python-pptx`. Tags run on the
+> **v1.22.x** patch line: `v1.22.0` (P0) → `v1.22.1..v1.22.5` (P1–P5) →
+> `v1.22.6` (P6 final = milestone release).
+
+Driven by user feedback that the deck looked "out of whack" and the
+desire to return to the clean, well-formatted style of the old
+`the-developer-experience.html`. Investigation revealed the "clean"
+reference was itself MARP output (using Marp's built-in `default` theme
++ an inline `style:` block); the current deck's standalone
+`nova-sp-theme.css` re-derives all base spacing from scratch and had a
+zero-padding bug (fixed in v1.22, but the standalone approach is
+fragile). The milestone delivers:
+
+- **Single-document consolidation** — `*-marp.md` becomes the sole
+  source of truth; the plain `.md` is deleted; speaker notes + talking
+  points are embedded as Marp HTML comments.
+- **Clean style restoration** — revert to `theme: default` + inline
+  `style:` block (S&P palette); `nova-sp-theme.css` retained as a
+  reference, retired from render.
+- **Self-contained HTML** — base64-inline all images for
+  redistribution.
+- **Parallel python-pptx generator** — structured, editable, S&P-themed
+  PPTX alongside the MARP image-of-slide PPTX.
+- **Targeted word-count trim** + "penetrate" term removal.
+
+**Phase count:** 7 (P0 pre-execution + 5 execution + 1 final).
+
+**Hard constraints:**
+- DO NOT change the deck narrative or the 4-beat arc (Problem → Solution
+  → Proof → Roadmap + Ask) — only trim word count.
+- DO NOT re-introduce badges, version strings, or internal citations.
+- DO NOT remove MARP — it stays for HTML + PPTX; python-pptx runs in
+  parallel.
+- `nova-sp-theme.css` is retained (not deleted) as a styling reference.
+
+### Requirements
+
+New requirements REQ-263..REQ-275 — see `REQUIREMENTS.md` §v1.23.
+Summary: consolidation (REQ-263,264), style restoration (REQ-265,266,267),
+image inlining (REQ-268), python-pptx generator (REQ-269,270), word-count
+trim + "penetrate" removal (REQ-271,272), CI/tests/README (REQ-273,274,275).