fix: report stackLimit exceedance as a parse error, not a thrown exception

[YuEfSaEDU]

Exceeding the configured stackLimit made CharReader::parse() — the engine behind fromJson-style parsing — terminate the process instead of reporting a parse failure: OurReader::readValue() called throwRuntimeError(), and the resulting Json::RuntimeError escapes parse()'s bool-return plus error-string contract and goes uncaught in typical callers.

This change reports the depth violation through the reader's existing error collection instead, so deeply nested input (for example ~1100 consecutive [) yields false with Exceeded stackLimit for nested object and/or array values. at the offending offset, consistent with every other parse error and with the existing JSON_USE_EXCEPTION=0 behavior. The CharReaderBuilder documentation for stackLimit is updated to match.

CharReaderTest/parseWithStackLimit now asserts the clean-failure contract for both exception modes, and a new parseDeeplyNestedArrayFailsCleanly test covers the issue's payload. The full unit suite (133 tests) passes on MSVC x64.

Fixes #1704

[greptile-apps]

Greptile Summary

This PR changes CharReader stack-limit violations from escaping runtime exceptions into ordinary parse failures with location-aware diagnostics.

• Replaces the exception-mode branch in OurReader::readValue() with the existing error-collection path.
• Documents the non-throwing CharReaderBuilder contract.
• Extends unit coverage across configured limits, mixed nesting, default limits, and deeply nested fuzz-style input.

Confidence Score: 5/5

The PR appears safe to merge because the depth guard remains active while its failure now follows the documented Boolean parse-result and diagnostic contract.

The changed branch records the depth violation before nested grammar recovery unwinds, preserving the error and returning a clean parse failure; the updated tests cover configured boundaries, mixed nesting, the default limit, and the reported location.

Important Files Changed

Filename	Overview
include/json/reader.h	Updates the CharReaderBuilder stack-limit documentation to describe parse failure and diagnostic reporting rather than an exception.
src/lib_json/json_reader.cpp	Routes OurReader depth-limit violations through addError() so recursive parsing unwinds and returns false without an escaping exception.
src/test_lib_json/main.cpp	Updates stack-limit assertions for both exception modes and adds regression coverage for deeply nested arrays and exact diagnostic locations.

Flowchart

%%{init: {'theme': 'neutral'}}%%
flowchart LR
  A[CharReader parse input] --> B[OurReader readValue]
  B --> C{Depth exceeds stackLimit?}
  C -- No --> D[Tokenize and build Value tree]
  C -- Yes --> E[Record stack-limit parse error]
  E --> F[Unwind nested grammar]
  F --> G[Return false with formatted diagnostics]
  D --> H[Return parse result]

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