#305 - extract calypso-sim into a standalone MQTT simulator crate

[bracyw]

Changes

Extracts the MQTT simulator out of the main calypso binary (deleting the in-tree src/bin/simulate.rs) into a standalone, detached-workspace crate at calypso-sim/ with four input modes — mock heartbeat, interactive keyboard, deterministic replay, and a JSON-RPC-over-stdio stream — kept from fighting over the same topic by a static ownership partition resolved once at startup (the heartbeat cedes any topic a driver owns, up front — no runtime negotiation). Interactive and replay share one recursive scenario model (an action is a list of publish/sleep/invoke steps), so there's no separate keymap-vs-script pair of files to coordinate. Also hoists the shared CAN data-model types (DecodeData/EncodeData/FormatData) into calypso-cangen so the sim reuses them without depending on the Linux-only calypso crate, removes the now-dead simulate path from main, ports the old Python VCU-mimic harness to broker-free Rust tests, keeps the simulate Docker entry point, and adds a path-filtered CI workflow for the crate.

Notes

• calypso-sim is its own detached workspace (empty [workspace], own Cargo.lock/target). It does not build from a top-level cargo build --all — cd calypso-sim first. It has its own path-filtered CI (calypso-sim-ci.yml) that runs only when the crate or its path-deps change.
• One recursive scenario model for the keyboard/replay side: an action is a named list of steps, and a step is publish · sleep · or invoke another action. Interactive binds an action to a key; --play <action> runs one by name (this replaces the old --script FILE); actions compose by invoking each other, so a scenario is one self-contained file. This collapses the previous four keymap entry shapes, the parallel KeyEntry/KeyMode enums, and the separate script parser into a single primitive — and steps are shape-disambiguated, so there's no order-dependent untagged matching. Invalid/cyclic invokes, duplicate keys, and bad publish-arity are rejected at load. The keymap/script formats were new in this PR, so there's no external consumer to break.
• Ownership is a static startup partition, not a runtime registry. The mock heartbeat and a foreground driver never negotiate at runtime: any topic the driver owns (a scenario's topics for --key-map/--play, auto-derived; nothing for --stream, where you reserve topics with --disable-topic) is removed from the heartbeat's set up front, so the two publish disjoint topics by construction — and the split is printed at startup. This deleted the Arc<RwLock<…>> ownership registry and the stream claim/release/silence/status RPCs; the stream protocol is now just publish/list_topics/ping.
• Data model went into calypso-cangen, not daedalus — daedalus is proc-macro = true and can't export plain types, while calypso-cangen is a normal lib both crates already depend on. Main's src/data.rs is now a thin re-export shim, so the decode/encode codegen macros (crate::data::…) are unchanged.
• Heartbeat mode renamed from autonomous/--auto to mock/--mock (flag, module, and docs).
• Sim CI fmt step uses plain cargo fmt --check, not --all — --all makes cargo-fmt walk the sim's path-deps up into the main workspace and try to format its generated src/proto, which never exists in the sim CI checkout.

Test Cases

All from inside calypso-sim/:

• cargo run -- --list-topics → prints every simulatable topic, then exits.
• cargo run → mock heartbeat; publishes randomized values on every topic with a sim_freq in the spec.
• cargo run -- --key-map manual_sim_buttons.keymap.json --mock → interactive + heartbeat; prints an Ownership: mock heartbeat drives N topic(s); M reserved for the driver … line showing the scenario's topics are ceded, and each action fires on its bound key.
• cargo run -- --key-map manual_sim_buttons.keymap.json --play demo → runs the demo action (its nested invokes + sleep_ms waits, in order), then exits.
• cargo run -- --stream, then feed {"jsonrpc":"2.0","id":1,"method":"publish","params":{"topic":"Wheel/Buttons/button_id","value":5}} → responds {"jsonrpc":"2.0","id":1,"result":{"ts_us":...}}.
• cargo test → 6 unit + 3 integration tests pass, no broker needed.
• cargo fmt --check and cargo clippy --all -- -D warnings → clean.

Checklist

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Closes #305