UX-08 2c: short refusals, error texts and option texts

Validator refusals name the setting by its label and key, say what is
wrong and what to change, and keep the rejected value and limit. Option
names and descriptions are short in en and nl; citations moved to DOCS
"For installers" and the test_translations citation check now pins the
instruction on the tab and the record in DOCS. No rule, key, schema,
default or exit code changed. Allowlist 167 -> 43 (log lines only).

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01LyR88rXETvwhTgx6yHE39p

goodwe_controller/app/price.py

@@ -1453,9 +1453,8 @@ def _validate_raw(points, caps):
         if abs(p.eur_per_kwh) > MAX_PLAUSIBLE_EUR_KWH:
             raise SourceUnavailable(
                 f"point at {p.start.isoformat()} is {p.eur_per_kwh} EUR/kWh, "
-                f"beyond +-{MAX_PLAUSIBLE_EUR_KWH} - the usual cause is a feed "
-                f"in EUR/MWh being read as EUR/kWh, which is a factor of 1000 "
-                f"and would make every hour look like an emergency")
+                f"beyond +-{MAX_PLAUSIBLE_EUR_KWH}, so the feed is probably in "
+                f"EUR/MWh")
         u = p.start.astimezone(timezone.utc)
         if seen is not None and u <= seen:
             raise SourceUnavailable(
@@ -1708,18 +1707,13 @@ def _points_from_columnar_json(body, expect_unit, scale,
     if len(times) != len(prices):
         raise SourceUnavailable(
             f"{COLUMNAR_TIME_KEY} has {len(times)} entries and "
-            f"{COLUMNAR_PRICE_KEY} has {len(prices)}; refusing to zip them. "
-            f"The short array would truncate the series silently, and a price "
-            f"series missing its last hours is one missing the evening peak - "
-            f"traded on as if complete, where no data at all would have "
-            f"switched arbitrage off (§11.4)")
+            f"{COLUMNAR_PRICE_KEY} has {len(prices)}, so the feed is cut short "
+            f"and none of it is used")
     unit = _columnar_unit(doc.get(COLUMNAR_UNIT_KEY, ""))
     if unit != _columnar_unit(expect_unit):
         raise SourceUnavailable(
             f"the feed reports {doc.get(COLUMNAR_UNIT_KEY)!r}, not "
-            f"{expect_unit!r}. This provider converts with a fixed factor of "
-            f"{scale}, so a changed unit is a factor of 1000 on every price "
-            f"with nothing downstream able to notice it")
+            f"{expect_unit!r}, so its prices cannot be converted")
     if doc.get("deprecated"):
         # Not a refusal: today's prices are still prices. But §11.4 makes a
         # dead feed look exactly like a quiet one, so the warning that the
@@ -2011,11 +2005,9 @@ class CustomFormula(PriceProvider):
             raise SourceUnavailable(f"price_formula: {e}")
         if spec is None:
             raise SourceUnavailable(
-                "price_provider is 'custom_formula' but price_formula is "
-                "empty, so there are no coefficients to price anything with. "
-                "validate.py refuses this configuration at startup; reaching "
-                "it here means the options blob changed under a running "
-                "add-on")
+                "“Dynamic price source” (price_provider) is 'custom_formula', "
+                "but “Your own tariff formula” (price_formula) is empty. "
+                "Restart the add-on to check the settings again")
         url = dayahead_feed_url(self.id, opts, since, until,
                                 self.FEED_BASE, self.BZN)
         check_egress(url, self.capabilities())