portfolio: drop rational/irrational + system-temperature from prompt

The base build_system_prompt() bakes in two artefacts that read fine
in the daily strategic log but cause repeated reviewer rejections on
the portfolio surface:

- The "Rational vs irrational" framework, which the model translates
  into IT/ES/FR/DE variants ("Razionalmente / Irrazionalmente",
  "Razionale se / Irrazionale se", etc.). Haiku reads the parallel
  contrast lists as the author working through their reasoning on
  the page and rejects as scratchpad.
- The mandatory "System temperature: [label] — …" closing line,
  which Haiku correctly flags as meta-commentary on this surface
  (it has no narrative anchor in a portfolio read).

Both are wired into the base prompt and don't add value here. Drop
them explicitly via an "# DO NOT include in this surface" override
block in _SYSTEM_OVERRIDES. The portfolio read is just plain
declarative commentary on the holdings now — opening posture
sentence, 3-5 paragraphs on concentration / tilt / currency /
winners-losers / what would invalidate, end of story.

Reviewer's rational-vs-irrational structural-device carve-out (added
in de3a9bf) stays — strategic log, indicator summaries, and digest
emails still legitimately use that framing.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

app/services/portfolio_analysis.py

@@ -257,18 +257,14 @@ implies X under scenario Y"), not advice ("buy X" / "sell Y" are forbidden).
 - ~350 words. No bullet lists. No buy/sell recommendations.
 - Do not repeat the input data verbatim — interpret it.
 
-# Rational vs irrational lens (mandatory)
-Carry the base prompt's rational-vs-irrational framing through to every
-paragraph of the portfolio read. For each section above, contrast:
-- The RATIONAL read: what the underlying factors (fundamentals,
-  macro/policy regime, valuation, currency dynamics) justify for this
-  exposure;
-- The IRRATIONAL read: what positioning, narrative momentum, sentiment
-  or flows are doing to that same exposure right now.
-Then name the GAP — does the holder's posture line up with the rational
-read, or is it riding the irrational one? A paragraph that names only
-the pie's numbers or only the macro backdrop, without placing the
-holding on this rational-vs-irrational axis, is incomplete.
+# DO NOT include in this surface (overrides the base prompt)
+- No "Rational vs irrational" framing, no "Rational:" / "Irrational:"
+  section labels, no parallel contrast lists. The base prompt asks
+  for this framework elsewhere; this surface is plain declarative
+  commentary on the holdings, not a comparative essay.
+- No "System temperature:" closing line. That artefact belongs to the
+  daily strategic log; here the analysis ends with the last paragraph.
+- No "Update mode" headers, no anchor-date callouts, no watch list.
 """