fix(i18n): make the Korean locale actually work end to end

Registering `ko` in the `Locale` union left seven locale-keyed tables
without an entry, so the build could not type-check and the safety
screens, the citation-coverage grader and the reference-range parser
read nothing at all for a Korean reader.

Three failures were not missing keys but wrong assumptions:

- The shared fold decomposes with NFD and strips U+0300-U+036F. Latin
  accents become plain letters, but Hangul decomposes into jamo, which
  are not in that range and survived — so folded Korean text was a jamo
  sequence no precomposed table entry could ever match. It recomposes to
  NFC now; every Latin, Polish and German fold is byte-identical.
- `normaliseLabKey` kept `[a-z0-9]`, which reduced every Korean analyte
  name to the empty string, so the derived index held none of them and a
  Korean cholesterol result reached a FHIR export uncoded.
- The reference-range parser had the hyphen and the dashes but not the
  tilde a Korean lab actually prints (`3.5~5.0`).

The Korean safety banks carry no `\b` next to a Hangul token — `\b` is
an ASCII `\w` boundary and Hangul is not `\w`, so `/\b증량/` matches
nothing — and the clause order is the mirror of the Latin banks, since
Korean closes with the verb. The dose patterns require a target-marking
particle for the same reason the Latin banks require "to"/"by": without
it the permitted restatement "7.5mg을 복용 중이고, 체중은 내려가고
있어요" tripped the lowering pattern.

The Coach and Insights prompts route `ko` down the reviewed English body
plus a Korean reply directive; there is no `safety-contracts.ko.yaml`, so
the native builder has no Korean ground rules to compose from.

docs/api/openapi.yaml

@@ -20248,6 +20248,7 @@ components:
             - es
             - it
             - pl
+            - ko
         practiceName:
           type: string
           maxLength: 120
@@ -22343,6 +22344,7 @@ components:
             - fr
             - it
             - pl
+            - ko
         today:
           description: "Optional override of the reference date used to resolve relative phrases (\"tomorrow\", \"next Monday\").
             Format: `YYYY-MM-DD`. Defaults to the server's UTC day."
@@ -23234,6 +23236,7 @@ components:
             - es
             - it
             - pl
+            - ko
           description: One of the interface locales this build ships.
       required:
         - locale
@@ -27714,6 +27717,7 @@ components:
             - fr
             - it
             - pl
+            - ko
         timezone:
           type: string
           minLength: 1
@@ -27929,6 +27933,7 @@ components:
                 - fr
                 - it
                 - pl
+                - ko
             - type: "null"
         timezone:
           type: string
@@ -46021,6 +46026,7 @@ components:
                 - es
                 - it
                 - pl
+                - ko
           required:
             - locale
           additionalProperties: false
@@ -66553,6 +66559,7 @@ components:
                 - fr
                 - it
                 - pl
+                - ko
             - type: "null"
         timezone:
           type: string