Add REPL set_offset and search_offset commands

[YSaxon]

Motivation

• Provide a way to directly set a library offset and to locate an in-memory bytestring for computing a library offset to complement calculate_offset.
• Make the search robust across platforms by enumerating readable mapped regions for a library and verifying uniqueness of matches.
• Give users a quick way to inspect context via hexdumps to verify search results before storing offsets.

Description

• Added REPL commands set_offset <library> <offset> and search_offset [<variable>] <library> <bytestring> <address> with parsers parseSetOffset and parseSearchOffset in src/main.c.
• Implemented helpers parse_search_bytes, append_region, find_bytes_in_regions, and dump_match_context and small MemoryRegion/MemoryMatch types to support searching and context dumping.
• Added platform-specific region enumeration used by search_offset: Linux via /proc/self/maps, Windows via GetModuleInformation + VirtualQuery, and macOS via dyld image lookup + mach_vm_region.
• Hooked the new commands into the REPL help text and dispatch; forward-declared printVariableWithArgInfo and included required platform headers.
• When a unique match is found, the code computes address_in_memory - address_provided and stores it via storeOffsetForLibLoadedAtAddress; if a variable name is supplied, the offset is also stored in that variable.

Testing

• Ran build configuration and compile with cmake -S . -B build and cmake --build build -j4, which completed successfully.
• Ran the full test suite with ctest --test-dir build --output-on-failure, and all tests passed (156/156 passed).

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Codex Task

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[chatgpt-codex-connector]

Fail set_offset when getOrLoadLibrary returns NULL

parseSetOffset stores an offset even if getOrLoadLibrary fails, so a bad or non-loadable library name silently writes liboffset_(nil) and reports success; this can corrupt later offset-based lookups that also use a null handle instead of surfacing a load error. Add a null-handle check before calling storeOffsetForLibLoadedAtAddress.

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[chatgpt-codex-connector]

Canonicalize library path before region-path suffix checks

The Linux/macOS region matcher requires mapped paths to end with resolve_library_path output, but that resolver can return non-canonical symlink paths (for example libfoo.so) while mapped image paths are canonicalized targets (for example libfoo.so.1), causing search_offset to report no readable regions even when the library is loaded. Canonicalizing the resolved path (or matching by inode/basename) avoids this false negative.

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