feat(#78): IMP-49 dx_sw_necessity partial Figma provenance fix (u1~u3)

Replace eyeballed PROMOTED green hex (#296B55, #123328) with verbatim
upstream values from figma_to_html_agent/blocks/1171281198/index.html:
- border + check mark: #1d4d3e (upstream :208 -webkit-text-stroke)
- header gradient: rgb(15, 50, 30) / rgb(60, 52, 34) (upstream :54, :64)

Document .f20b__* as authoring-ordinal namespace (NOT Figma frame_id
1171281198); structural link via data-frame-id attribute. No selector
rename, no catalog edit.

Add focused regression test (tests/test_imp49_partial_figma_provenance.py)
extracting <style>-block hex/rgb/rgba literals and asserting non-whitelisted
literals exist byte-identically in upstream source. Whitelist limited to
neutrals (#fff, #1a1a1a) + shared zone-title token (#000, #883700,
rgba(50,44,30,0.4)).

Scope: dx_sw_necessity_three_perspectives.html only. 19 missing partials,
.fNb__ rename, full 32-contract audit deferred to follow-up axes.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

templates/phase_z2/families/dx_sw_necessity_three_perspectives.html

@@ -18,11 +18,18 @@ builder/parser 0.
 - figma_to_html (1171281198) = source/evidence — 386-line index.html + assets/.
 - Phase Z = runtime — 본 commit adds catalog + partial + smoke fixture.
 
-PROMOTED — CSS :
-  - 3 column header bg : dark green (`#296B55` family, Figma green theme)
-  - header text white bold + green accent
-  - title gradient (#000 → #883700, F13/F14/F12/F11/F18 zone-title family)
-  - card border + bullet markers (green family)
+PROMOTED — CSS (verbatim from figma_to_html_agent/blocks/1171281198/index.html) :
+  - 3 column header bg : two-stop vertical adaptation of upstream horizontal
+    banner gradient end-stops — start `rgb(15, 50, 30)` (upstream :54, stop 0%),
+    end `rgb(60, 52, 34)` (upstream :64, stop 100%). Adaptation surface =
+    direction (90deg → 180deg) + stop count (11 → 2); colors verbatim.
+  - header text white bold + green accent (white #fff verbatim, see upstream
+    :202 `color: #ffffff`)
+  - title gradient (#000 → #883700, F13/F14/F12/F11/F18 zone-title family;
+    shared zone-title token, not from this frame)
+  - card border + bullet markers : `#1d4d3e` (upstream :208 `.card-title-1`
+    `-webkit-text-stroke: 1.5px #1d4d3e`). Replaces earlier eyeballed
+    `#296B55` approximation (IMP-49 #78 u1).
 
 NOT PROMOTED (P1 case-by-case, compact zone fit) :
   - 상단 dark green banner (Figma 의 큰 visual 영역, MDX 의 *title 만* 핵심)
@@ -80,7 +87,7 @@ slots :
   }
   .f20b__col {
     display: flex; flex-direction: column;
-    border: 2px solid #296B55;        /* PROMOTED — green family from Figma */
+    border: 2px solid #1d4d3e;        /* PROMOTED — verbatim from upstream :208 (.card-title-1 -webkit-text-stroke) */
     border-radius: 8px;
     overflow: hidden;
     background: #fff;
@@ -89,7 +96,7 @@ slots :
 
   /* header bar (top of each card, dark green per Figma) */
   .f20b__header {
-    background: linear-gradient(180deg, #296B55 0%, #123328 100%);   /* PROMOTED — Figma green theme */
+    background: linear-gradient(180deg, rgb(15, 50, 30) 0%, rgb(60, 52, 34) 100%);   /* PROMOTED — verbatim end-stops from upstream :54 (0%) and :64 (100%); 11-stop horizontal banner adapted to 2-stop vertical card header */
     color: #fff;
     font-weight: 700;
     font-size: var(--font-sub-title);
@@ -121,11 +128,20 @@ slots :
     content: "\2713";          /* ✓ check mark — green theme */
     position: absolute;
     left: 0; top: 0;
-    color: #296B55;            /* PROMOTED — green family */
+    color: #1d4d3e;            /* PROMOTED — verbatim from upstream :208 (.card-title-1 -webkit-text-stroke) */
     font-weight: 700;
   }
 </style>
 
+<!-- IMP-49 #78 u2 — namespace scope note :
+     `.f20b__*` is an AUTHORING-ORDINAL namespace (ordinal "20b" in this catalog's
+     authoring sequence), NOT the Figma frame_id 1171281198. The structural link
+     to the source frame is the `data-frame-id="1171281198"` attribute on the
+     root <div> below. Cross-frame `.fNb__` class reuse is forbidden — class names
+     MUST stay within their owning partial (see [[feedback_partial_figma_audit]]).
+     Selector names and catalog references (frame_contracts.yaml :492,:497,:502)
+     are intentionally unchanged in this unit. -->
+
 <div class="f20b" data-frame-id="1171281198" data-template-id="dx_sw_necessity_three_perspectives">
   <div class="f20b__title">{{ slot_payload.title }}</div>
   <div class="f20b__cols">

tests/test_imp49_partial_figma_provenance.py

@@ -0,0 +1,64 @@
+"""IMP-49 #78 — partial Figma provenance regression test.
+
+For `templates/phase_z2/families/dx_sw_necessity_three_perspectives.html`,
+extract color literals (hex + rgb/rgba, whitespace-preserving) from the
+<style> block, then assert each non-whitelisted literal exists byte-identically
+in `figma_to_html_agent/blocks/1171281198/index.html`.
+
+Whitelist composition (per Stage 2 EXIT REPORT, IMP-49 #78):
+  - Neutrals: #fff, #1a1a1a (page-default text / surface)
+  - Shared zone-title token: #000, #883700, rgba(50,44,30,0.4)
+    (F13/F14/F12/F11/F18 zone-title family — not sourced from frame 20)
+
+Guardrails:
+  - rgb()/rgba() literals matched as substrings, so whitespace (single space
+    after comma) is preserved byte-for-byte against upstream.
+  - Failure message surfaces the offending literal and the whitelist.
+"""
+from __future__ import annotations
+
+import re
+from pathlib import Path
+
+PROJECT_ROOT = Path(__file__).parent.parent
+PARTIAL_PATH = (
+    PROJECT_ROOT / "templates" / "phase_z2" / "families"
+    / "dx_sw_necessity_three_perspectives.html"
+)
+UPSTREAM_PATH = (
+    PROJECT_ROOT / "figma_to_html_agent" / "blocks" / "1171281198" / "index.html"
+)
+
+COLOR_WHITELIST = frozenset({
+    "#fff",
+    "#1a1a1a",
+    "#000",
+    "#883700",
+    "rgba(50,44,30,0.4)",
+})
+
+HEX_RE = re.compile(r"#(?:[0-9a-fA-F]{8}|[0-9a-fA-F]{6}|[0-9a-fA-F]{4}|[0-9a-fA-F]{3})\b")
+RGB_RE = re.compile(r"rgba?\([^)]*\)")
+STYLE_RE = re.compile(r"<style>(.*?)</style>", re.DOTALL)
+
+
+def _extract_style_block(html_text: str) -> str:
+    match = STYLE_RE.search(html_text)
+    assert match, f"partial {PARTIAL_PATH} must contain a <style> block"
+    return match.group(1)
+
+
+def test_partial_color_literals_byte_identical_to_upstream() -> None:
+    partial_text = PARTIAL_PATH.read_text(encoding="utf-8")
+    upstream_text = UPSTREAM_PATH.read_text(encoding="utf-8")
+    css_text = _extract_style_block(partial_text)
+    literals = HEX_RE.findall(css_text) + RGB_RE.findall(css_text)
+    assert literals, "partial <style> must contain at least one color literal"
+    missing = sorted(
+        {lit for lit in literals if lit not in COLOR_WHITELIST and lit not in upstream_text}
+    )
+    assert not missing, (
+        "Non-whitelisted color literals in partial must be byte-identical to "
+        f"upstream {UPSTREAM_PATH.relative_to(PROJECT_ROOT)}. "
+        f"Missing: {missing}. Whitelist: {sorted(COLOR_WHITELIST)}."
+    )