Move pattern matching logic out of Instruction

[Vladyslav-Kuksiuk]

This PR:

• moves the pattern matching logic from instruction.go to pattern.go;
• improves the readability of some documentation.

[Copilot]

Pull request overview

This PR refactors embed-code-go’s embedding instruction parsing by relocating source-line pattern matching logic from Instruction into Pattern, while also updating documentation to reflect current CLI/config options and improve wording.

Changes:

• Refactored pattern compilation/matching into embedding/parsing/pattern.go (multi-line patterns compiled into per-line matchers; matching exposed via Pattern.FindIn).
• Updated Instruction creation and matching to use the new pattern API, including returning a proper error for invalid glob patterns.
• Documentation updates for CLI/config fields (doc-excludes, info, stacktrace) and build instructions.

Reviewed changes

Copilot reviewed 8 out of 8 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
README.md	Documents additional CLI/config options and adjusts manual build instructions.
main.go	Documents info and stacktrace flags in the top-level usage comment.
fragmentation/fragment.go	Improves/internalizes doc comments for fragment helpers and constants.
embedding/parsing/pattern.go	Moves pattern compilation/matching logic here and introduces FindIn for range matching.
embedding/parsing/instruction.go	Switches instruction matching to Pattern.FindIn and validates pattern compilation at parse time.
embedding/parsing/instruction_test.go	Adds coverage for invalid glob patterns producing a user-facing error.
EMBEDDING.md	Readability/wording fixes and minor formatting corrections.
configuration/configuration.go	Improves documentation comments and clarifies defaults.

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[Oleg-Melnik]

LGTM with resolved comments from Copilot prior to merging.