feat(parser): add compiler-aware parsing for v0.2.0

[ikelaiah]

PasWeave v0.2.0: compiler-aware parsing

Suggested PR title:

feat(parser): add compiler-aware parsing for v0.2.0

Summary

This PR completes the active v0.2.0 roadmap milestone. PasWeave can now
parse the same conditional interface as a configured Free Pascal build instead
of silently relying on the documentation host's defaults.

No v0.3.0 or later roadmap work is included.

What changed

• Added repeatable --unit-path, --include-path, and --define options.
• Added explicit, normalized --target-os and --target-cpu options.
• Defined deterministic precedence for defaults and repeated command-line
  settings.
• Added transitive project-unit and nested-include resolution through
  configured paths, with first-match search-path ordering.
• Kept fcl-passrc types behind the parser adapter and out of the public
  model.
• Added stable diagnostics for invalid settings, missing paths, and missing or
  unreadable includes.
• Added focused fixtures for conditional declarations, target selection,
  nested and missing includes, competing search paths, and transitive units.
• Updated CLI help, README guidance, detailed documentation, roadmap status,
  changelog, version metadata, and release notes.

Compatibility

• Supplying no compiler settings preserves the previous host-target behavior
  and parser arguments.
• All 77 generated documented-API files matched the pre-change baseline
  byte-for-byte by SHA-256 when no new settings were supplied.
• Direct file and directory inputs and the default /// documentation flow
  remain supported end to end.
• Generated JSON remains model schema version 1.

Validation

• Complete automated test suite passes with Free Pascal 3.2.2.
• All checked-in Markdown and HTML golden outputs pass unchanged.
• Portable Windows release build and isolated smoke test pass.
• Configured mathlib-fp audit parses all 45 units into 2,338 symbols with
  zero warnings or errors.
• All 163 configured mathlib-fp output files match the unconfigured
  baseline byte-for-byte.
• Release metadata reports 0.2.0.

Known limits

• Lazarus .lpi and .lpk files are not interpreted in this release; their
  compiler values must be supplied manually.
• Unit paths resolve Pascal source files (.pas and .pp), not compiled
  .ppu files.
• Target OS and CPU values are validated independently; PasWeave does not
  claim that every possible pair is an FPC-supported backend combination.

Release checklist

• PasWeaveVersion, its regression assertion, and README version badge
  are set to 0.2.0.
• CHANGELOG.md contains the 0.2.0 entry.
• RELEASE_NOTE_v0.2.0.md is ready for the GitHub release description.
• PR checks pass.
• Merge this PR into main.
• The post-merge Windows build on main passes.
• Tag the verified merge commit as v0.2.0 and push the tag.
• Confirm the tag workflow publishes pasweave.exe and
  pasweave.exe.sha256 to the GitHub release.