fix(javascript): preserve semantic gaps for unparseable sources

Successful worker transport can carry an explicit failed parser status
with no semantic projection. Preserve that producer fact through the
shared source-availability interpretation used by full and incremental
graph construction, rather than dropping the source's semantic scope.

Retain the module when capacity permits, per-family incomplete-module
unknowns, and unknown omitted extents. Preserve existing operational
failure reasons and limits without classifying syntax as resource loss.
Document this coverage behavior.

Validation: regression-first run had 3 expected failures; all 22 selected
projection and public CLI source-selection/HTML cases passed after repair.
No JavaScript target execution or live external provider was involved.

docs/javascript-artifact-reconstruction.md

@@ -204,6 +204,13 @@ those missing bytes. New inventories preserve an ASAR companion declaration as
 unavailable bytes belonged to a companion. See [MCP integrity handling](mcp-contracts.md#integrity-record-and-continue)
 for the tool-result contract.
 
+JavaScript whose syntax cannot be parsed retains unavailable semantic coverage
+with `incomplete-module` unknowns for each semantic family and unknown omitted
+node and relation extents. The source module is retained when node capacity
+permits. A parser failure alone does not imply resource truncation or a named
+resource limit. Decoding failures and deliberately
+unselected sources retain the same explicit semantic coverage gap.
+
 HTML whose bytes are not valid UTF-8 retains its file observation and an unknown
 `parse-html-script-references` scope with artifact-byte authority. Reference
 discovery was unavailable; zero retained script links does not establish that