[hsusul]

Why

Later P1 checks need a reproducible fake archive. No check should read real agent history.

What changed

• Add crates/lore-core/examples/synth.rs. It takes <out_dir> <claude_count> <codex_count> <seed> and calls lore_core::synthetic::generate.
• Add scripts/synth-archive.sh. It runs the example in release mode and passes the exit code through.
• A missing or bad argument prints a one-line usage to stderr and exits 2.
• The script keeps the caller's cwd, so a relative <out_dir> resolves where the caller is.

Scope

• Two new files. No other file is touched. No Cargo.toml change was needed, because Cargo finds examples/ on its own.
• lore_core::synthetic is unchanged.

Blast Radius

• None at runtime. The example is not built by cargo build or shipped in the app.
• cargo clippy --all-targets and cargo test now also compile the example.

Verification

• scripts/synth-archive.sh /tmp/p1-0-a 30 20 7 printed /tmp/p1-0-a and claude 30 codex 20, exit 0.
• A second run into /tmp/p1-0-b and diff -r /tmp/p1-0-a /tmp/p1-0-b printed nothing.
• find counted 30 files under claude/projects and 20 under codex/sessions.
• lorectl scan --archive /tmp/p1-0-arch with CLAUDE_CONFIG_DIR and CODEX_HOME set to the generated homes and LORE_ARCHIVE_DIR unset reported ingested 50 skipped 0 failed 0.
• lorectl search health --archive /tmp/p1-0-arch returned hits (41 output lines).
• Counts of 0 5 and 5 0 wrote only Codex files and only Claude files, exit 0.
• No arguments, a missing seed, a non-numeric count, and an extra argument each printed the usage line and exited 2. The missing-seed run created nothing.
• Into a directory holding other/note.txt and two unrelated .jsonl files, the generator left their SHA-1 sums unchanged and added 50 session files.
• time scripts/synth-archive.sh /tmp/p1-0-big 3000 1000 7, three runs: 4.55 s, 8.43 s, 3.51 s. The median is 4.55 s against a 60 s budget. The output is 3000 and 1000 files, 16 MB.
• cargo fmt --all -- --check passed.
• cargo clippy -p lore-core -p lore-ipc -p lorectl --all-targets --all-features -- -D warnings passed.
• cargo test -p lore-core synthetic passed 7 tests in the library target.

Not verified here:

• lorectl mcp is not on main yet (PR 15), so the search_sessions check is not run.
• main's CI "Rust core" job is red from an unrelated egress-sandbox issue that PR 16 fixes. This PR does not touch it.
• /deslop and /no-comments are not installed here, so both were skipped.