Dogfood round 2: report ${...} parse columns correctly; name JS/Python string equivalents

[b-macker]

Summary

Two diagnostics fixes from repo-sentinel round 2 (the dogfooding project):

• Interpolation parse errors (a regression from Literal ${ in strings, one interpolation splitter, errors that teach #258). When a string not on line 1 contains ${...} that isn't valid NAAb, the "Parser said" line printed Parse error at line 2, column 11. The line was the file line, but the column was a position inside ${...}, so the pair pointed nowhere real.
  • Literal ${ in strings, one interpolation splitter, errors that teach #258 shifted the tokens inside ${...} to the string's file line, so runtime errors there point at the right line.
  • That moved the inner parse error off "line 1", and the rewrite to "character N of the expression" only matched "line 1". It now matches any line.
• string.slice suggested split(). The "did you mean" suggestion is chosen by edit distance, so it picked split. Names people and LLMs commonly reach for from JavaScript and Python now point at the NAAb equivalent, with an example.

Round 2 also confirmed that all six round-1 findings are fixed on the current build (F-001 to F-006).

Changes

• include/naab/string_interpolation.h: formatInterpolationError rewrites the inner parse position to "at character N of the expression" whatever line it reports.
• src/stdlib/string_impl.cpp: synonym hints for:
  • slice/substr → substring. The end index is exclusive, like slice.
  • includes → contains.
  • padStart/rjust → pad_left, and padEnd/ljust → pad_right.
  • trimStart/trimEnd/trimLeft/trimRight → trim.
  • replaceAll → replace, which already replaces every occurrence.
  • Each mapping was checked against actual behaviour first.
• tests/parser/test_dogfood_hints.sh: 7 new checks.

Test Plan

• test_dogfood_hints.sh passes 17/17.
  • Against the previous build, all 6 new checks fail and the control (S-00, string.substring still works) passes.
  • My first draft of the S checks passed S-01 on the old build, because "substring" also appeared in the old message's "Available:" list. They now match the suggestion text itself.
• test_string_interp_escape.sh passes 25/25.
• test_error_msg_leaks.sh passes 874/874.

🤖 Generated with Claude Code

https://claude.ai/code/session_01ELUfjXZvx8kzXo1UJjrAhC

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NAAb Governance Report

Metric	Count
Files checked	16
Passed	16
Failed	0

All governance checks passed!

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