Support efficient one-shot diffs and linked-binary reports

[Fabus1184]

Improve CLI workflows for large linked binaries:

• Scope objdiff-cli diff to the requested symbol when one is provided, while preserving object-wide symbol and section indexes for relocations.
• Allow objdiff-cli report generate to operate directly on --target / -1 and --base / -2 object files without requiring a project configuration.
• Add a summary-only diff path for reports that avoids retaining detailed instruction and data edit rows.
• Use block-based comparison for large linked data sections to avoid pathological diff performance.
• Preserve linked section addresses, avoid combining linked sections as though they were relocatable, and correct generated section-symbol ranges.
• Index symbol and ordering lookups to avoid repeated linear scans.

Together, these changes make single-symbol inspection and whole-binary report generation substantially faster and more reliable. They also prevent unrelated malformed data symbols from aborting a requested symbol diff.

Added coverage for:

• single-symbol x86 diffs;
• missing symbol mappings and common symbols;
• summary diffs omitting detailed rows;
• linked section addresses and section-symbol sizes;
• preventing linked sections from being combined.