build(examples): standardize example workflow around ELF binaries, remove unused .bin artifacts

[mahantybiplab]

Motivation

The example docs and build_all.sh instructed users to strip ELF headers with objcopy, producing raw .bin files. However, zp1-executor's ElfLoader requires ELF headers to load memory segments — passing a stripped binary causes an Invalid ELF file: Invalid magic error.

More importantly, no code in the repository ever consumed these .bin files. They were being generated, committed, and maintained purely as a side-effect of a build step that served no purpose. This PR removes the objcopy step, the .bin files it generated, and the documentation referencing both.

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Key Changes

CLI & Execution

• Smarter path resolution: crates/cli/src/main.rs now resolves bare example names to their compiled ELF artifacts at target/riscv32im-unknown-none-elf/release/<name>, so cargo run --release -- prove --bin fibonacci works without specifying the full path.

Build Tooling

• Removed objcopy requirement: examples/build_all.sh no longer requires LLVM/binutils. It builds and verifies ELF binaries only.

Cleanup & Documentation

• Removed stale .bin files from example directories — these were unused artifacts with no consumers anywhere in the codebase.
• Updated README.md and individual example docs to reflect the simplified CLI usage.
• Updated .gitignore to exclude proofs/ and other transient build artifacts.

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Verification

• All 25 examples compiled successfully via build_all.sh for riscv32im-unknown-none-elf.
• ElfLoader correctly parses headers and memory segments from unstripped ELF files.
• cargo run --release -- prove --bin fibonacci resolves the ELF path and proves successfully end-to-end.
• Full test suite passes: cargo test --workspace (162 prover tests + 16 integration tests).

[Copilot]

Pull request overview

This PR standardizes the examples workflow to use ELF binaries end-to-end (aligning with ElfLoader requirements), removes the unused .bin artifacts, and updates CLI/docs so examples can be proved by name instead of requiring a pre-stripped raw binary.

Changes:

• Remove objcopy/raw .bin generation from example build workflow and delete committed .bin artifacts.
• Add CLI path fallback to resolve --bin <example-name> to the corresponding compiled ELF under examples/target/.../release/.
• Update example documentation and .gitignore to reflect the ELF-only flow and ignore generated proofs.

Reviewed changes

Copilot reviewed 9 out of 35 changed files in this pull request and generated 10 comments.

Show a summary per file

File	Description
crates/cli/src/main.rs	Adds fallback resolution for prove --bin <name> into the examples ELF output directory.
examples/build_all.sh	Stops generating .bin files; now builds ELF artifacts only and prints ELF sizes.
examples/README.md	Updates example commands to remove objcopy and use prove --bin <name> (but needs follow-up consistency fixes).
examples/fibonacci/README.md	Updates build/run instructions to use ELF-only proving flow.
examples/keccak/README.md	Updates build/run instructions to use ELF-only proving flow.
examples/sha256/README.md	Updates build/run instructions to use ELF-only proving flow.
examples/memory-test/README.md	Updates build/run instructions to use ELF-only proving flow.
examples/ecrecover/README.md	Updates build/run instructions to use ELF-only proving flow.
.gitignore	Ignores /proofs output directory.
.vscode/settings.json	Removes editor-specific settings file from the repo.

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